cleaning 96 and 97 LX450 and land cruiser steering wheel for intermittent horn

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So I wrote all that without looking at the circuit diagram, so here a few nuggets:

The connector (C14 on the EWD) terminals 9, 10 are for the horn circuit. This connector is tucked under the column. Terminals 9,10 in the connector are the connection to ground. FWIW, the terminals in the connector are numbered to to bottom, left to right in the female half (the male is opposite). If the connector diagram has a X in a terminal spot, there's no conductor/terminal there. A dot means there is. The convention Toyota uses in these EWDs is the terminals in the connectors pertinent to the circuit you are looking at are numbered. These numbers correspond to the circuit diagram.

The ground, for this circuit, is behind the plastic kick panel cover, next to your left foot position when driving. It woudn't hurt to remove the scre, clean both the sheetmetal panel and ring terminal and reassemble. You can check the ground by connecting the other end of that wire to your DMM and the ground lead (of the DMM) to another screw in the panel somewhere. If you have a good ground you'll see it (or hear it, depending on your DMM).

The other information on the bottom of the page refer to the groundpoints, connector joining and relay diagrams, which are also handy to have. They are in the EWD; look for it in the Resources section.

Since you have observed the horn/warning flasher is on the same circuit, and the flashers, relay and horns work, the problem is probably limited to the horn circuit between the steering wheel and the ground at the kickpanel.
THANK YOU. i appreciate all of this and will get to work. i will also crack my electrical manual and review the toyota document which didn't seem to print properly for me last night. i appreciate the opportunity to make more headway with this topic!
 
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So I wrote all that without looking at the circuit diagram, so here a few nuggets:

The connector (C14 on the EWD) terminals 9, 10 are for the horn circuit. This connector is tucked under the column. Terminals 9,10 in the connector are the connection to ground. FWIW, the terminals in the connector are numbered to to bottom, left to right in the female half (the male is opposite). If the connector diagram has a X in a terminal spot, there's no conductor/terminal there. A dot means there is. The convention Toyota uses in these EWDs is the terminals in the connectors pertinent to the circuit you are looking at are numbered. These numbers correspond to the circuit diagram.

The ground, for this circuit, is behind the plastic kick panel cover, next to your left foot position when driving. It woudn't hurt to remove the scre, clean both the sheetmetal panel and ring terminal and reassemble. You can check the ground by connecting the other end of that wire to your DMM and the ground lead (of the DMM) to another screw in the panel somewhere. If you have a good ground you'll see it (or hear it, depending on your DMM).

The other information on the bottom of the page refer to the groundpoints, connector joining and relay diagrams, which are also handy to have. They are in the EWD; look for it in the Resources section.

Since you have observed the horn/warning flasher is on the same circuit, and the flashers, relay and horns work, the problem is probably limited to the horn circuit between the steering wheel and the ground at the kickpanel.
hey man. thanks very much for a very welcome opportunity to revisit this stuff. it's super helpful to have someone break it down.
i xeroxed the intro to the electrical manual which i will read again and i found something i saved for testing relays. so i can test the relay and report back.
i have a pair of 18" alligator leads on my bike but i need to make a spare pair to keep at home. so i need to find where you recommended the gauge for these because i would like to have a proper test kit.
also i can't accurately read gauge of wire just yet so i think i should just use a pair of wire strippers to make sure i am using the right gauge since i don't remember which coil or wire here is what gauge.
but a couple quick other questions please?
from the sounds of it you recommend having a couple pairs or 3 - 4' long - well - test leads with a pair of spades? one spade on each end? or would it be better to buy some alligator clips for this? or can i use the ones here for that? i have a bit of a kit of terminals over here. does it matter what size i use if these should be spades?
also i have these sort of splitters in one office the images here. one of them i think i would use in something like a fuse box to piggyback some power? or is this a very bad idea? or what if anything would i use these for? or could i use one or the other of these for test leads?
lastly, do you know how to test the horns? do i need to kind of test them in parallel somehow? or daisy chained or whatever?
i just grabbed rhis test light and you can see they both light up meaning current is going through them but not sound. so i must be missing something about testing a horn i think?

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I have found the smaller alligator clips are the most useful. The spade connectors, maybe not, because you'll only use them to troubleshoot circuits inside a connector (the plastic parts that clip together), to verify that the wire hasn't separated from the terminals (rare, but it does happen, especially if someone separated them by pulling on the wires and not the connector housings). For those, it's most useful to have the same terminals as are in the connectors themselves. The connectors and terminals are mostly Sumitomo, and Ballenger Motorsports carries, or can get, most of them.

Having said that, I usually just use the probes from the DMM. It's not the best setup, and sometimes it feels like you need three hands, but it works.

The two horns are separate elements, they can be tested separately. If I remember correctly (I don't have one in front of me), the wiring to the horn has a positive and ground; if so, you need to have both in the connector. It's below freezing here, so I'm not going outside to check.

FWIW, those horns are listed for Camry, Supra and LandCruiser, from 1986 to 1997.
 
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I'm sorry for sticking my nose in here, but this is like watching a car crash in slow motion. And no, I didn't read through this entire thread. It's too damn painful and @Malleus deserves some sort of award for his patience.

The schematic should be the VERY FIRST THING you look at, not the last. All of the information is right in front of you.

Subdivide the circuit by removing the relay.
Do you get a constant +12 at pin 2 of the relay socket?
Do you get a good constant ground at pin 1 of the relay socket with the horn switch pressed?
If you jump pin 2-3 of the relay socket does the horn beep?

If you answered "no" to any of the above questions, you now know where in the circuit the problem lies.
If you answered "yes" to all the questions, then the issue is with the relay.
 
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I'm sorry for sticking my nose in here, but this is like watching a car crash in slow motion. And no, I didn't read through this entire thread. It's too damn painful and @Malleus deserves some sort of award for his patience.

The schematic should be the VERY FIRST THING you look at, not the last. All of the information is right in front of you.

Subdivide the circuit by removing the relay.
Do you get a constant +12 at pin 2 of the relay socket?
Do you get a good constant ground at pin 1 of the relay socket with the horn switch pressed?
If you jump pin 2-3 of the relay socket does the horn beep?

If you answered "no" to any of the above questions, you now know where in the circuit the problem lies.
If you answered "yes" to all the questions, then the issue is with the relay.
any info is welcome jon.
not sure why you feel the need to criticize the thread. move along if it's not your cup of tea. i mean this is general advise your parents gave you isn't it?
that said, any idea why the horns are not sounding? positive goes to the spade here? and it is grounded to the negative pole?
i can hear the relay click when i push the horn. but it does not work regularly. in fact it DID work regularly after putting the clock spring in.
then it started not working much the next day. then the day following it didn't work even more.
now i can barely get it to work at all.
so the relay clicks.
now i am testing the relay and the horn.
how am i not testing the horn correctly is the question and if i am testing it correctly why is it only working intermittently in the truck is the question you need to be tracking.
also - i'd appreciate it if you keep the comments on the facts and if not move it along.
also, criticizing someone for not being able to read an electrical diagram of being fluent with low voltage electricity (or being a little slow about testing electrical circuits) is a little rich isn't it?

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I have found the smaller alligator clips are the most useful. The spade connectors, maybe not, because you'll only use them to troubleshoot circuits inside a connector (the plastic parts that clip together), to verify that the wire hasn't separated from the terminals (rare, but it does happen, especially if someone separated them by pulling on the wires and not the connector housings). For those, it's most useful to have the same terminals as are in the connectors themselves. The connectors and terminals are mostly Sumitomo, and Ballenger Motorsports carries, or can get, most of them.

Having said that, I usually just use the probes from the DMM. It's not the best setup, and sometimes it feels like you need three hands, but it works.

The two horns are separate elements, they can be tested separately. If I remember correctly (I don't have one in front of me), the wiring to the horn has a positive and ground; if so, you need to have both in the connector. It's below freezing here, so I'm not going outside to check.

FWIW, those horns are listed for Camry, Supra and LandCruiser, from 1986 to 1997.
thanks a lot malleus.
i try to pick up this topic and learn a little at a time. this is a nice opportunity.
attached are pics of the horn and horn connector. i assume these are the positive from the battery.
i cleaned up the ground a little when i first had this problem.
any ideas on how best to clean these connectors?
also any idea why it is not testing as working in the bench test? maybe i need to check the power coming out of my test battery? and charge that up?

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I have found the smaller alligator clips are the most useful. The spade connectors, maybe not, because you'll only use them to troubleshoot circuits inside a connector (the plastic parts that clip together), to verify that the wire hasn't separated from the terminals (rare, but it does happen, especially if someone separated them by pulling on the wires and not the connector housings). For those, it's most useful to have the same terminals as are in the connectors themselves. The connectors and terminals are mostly Sumitomo, and Ballenger Motorsports carries, or can get, most of them.

Having said that, I usually just use the probes from the DMM. It's not the best setup, and sometimes it feels like you need three hands, but it works.

The two horns are separate elements, they can be tested separately. If I remember correctly (I don't have one in front of me), the wiring to the horn has a positive and ground; if so, you need to have both in the connector. It's below freezing here, so I'm not going outside to check.

FWIW, those horns are listed for Camry, Supra and LandCruiser, from 1986 to 1997.
one more side thread on this topic please? on testing voltage drop? dial set to DC V. then you are grounding the black probe. then red probe before the component? or before the relay? or the connector? or whatever? then you take that reading?
then you do this for after the component?
and you only want to see 0.1Vif you are testing wiring? and if you are testing a component it might have a higher voltage drop?
also what was "RPM" next to the DC V on the dial please?

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thanks a lot malleus.
i try to pick up this topic and learn a little at a time. this is a nice opportunity.
attached are pics of the horn and horn connector. i assume these are the positive from the battery.
i cleaned up the ground a little when i first had this problem.
any ideas on how best to clean these connectors?
also any idea why it is not testing as working in the bench test? maybe i need to check the power coming out of my test battery? and charge that up?

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The temperature here is now (in theory), above freezing, so I just did this on my 80, the same way you did in your photo. If the horn is good, it'll make noise. Mine are something over 85 dB, connected directly to the battery. Your power supply has to be at least 12VDC.

I'd recommend spraying some CRC plastic safe cleaner in both connectors (the wiring harness and horn) before you put it back together. I use this for all my connectors; a stiff brush won't hurt. The yellow part is plastic, so don't scrub too hard on it if you're using a metal brush.
 
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one more side thread on this topic please? on testing voltage drop? dial set to DC V. then you are grounding the black probe. then red probe before the component? or before the relay? or the connector? or whatever? then you take that reading?
then you do this for after the component?
and you only want to see 0.1Vif you are testing wiring? and if you are testing a component it might have a higher voltage drop?
also what was "RPM" next to the DC V on the dial please?

View attachment 2908503
Q 1-7 (I'm counting question marks), A; yes
Q8, A: no
Q9, A: yes
Q10, A: maybe, depends on the component, you need the spec on the component. The EWD section will tell you the voltage required for the specific component.
Q11, A: this is specific to the Fluke 88; it's an automotive tester, and it has settings (1 & 2) to measure ENGINE RPM, works like a tach. Your meter may be different. I use a Fluke 115, because I have it. You can get almost all electrical measurements you need to do basic troubleshooting with any meter. They're like cars. They all get you down the road, some cost more have more bells and whistles, and break more often.

HTH
 
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any info is welcome jon.
not sure why you feel the need to criticize the thread. move along if it's not your cup of tea. i mean this is general advise your parents gave you isn't it?
that said, any idea why the horns are not sounding? positive goes to the spade here? and it is grounded to the negative pole?
i can hear the relay click when i push the horn. but it does not work regularly. in fact it DID work regularly after putting the clock spring in.
then it started not working much the next day. then the day following it didn't work even more.
now i can barely get it to work at all.
so the relay clicks.
now i am testing the relay and the horn.
how am i not testing the horn correctly is the question and if i am testing it correctly why is it only working intermittently in the truck is the question you need to be tracking.
also - i'd appreciate it if you keep the comments on the facts and if not move it along.
also, criticizing someone for not being able to read an electrical diagram of being fluent with low voltage electricity (or being a little slow about testing electrical circuits) is a little rich isn't it?

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View attachment 2908449
Your bench setup looks correct. Check the voltage of the battery. If it's at least 12V, and the horn doesn't hurt your ears, the horn is defective.

If you want to cheat this circuit check do this: connect your meter to the positive terminal in the horn connector and the negative to the ground at the horn mount. You should see either a continuous circuit (Ohm setting) or about 12V (VDC setting) when the horn switch on the steering wheel is pressed. You can get away with this method for this circuit because it's simple and self contained. If you don't get a continuous/12VDC result, power's not getting to the horn. This is not the proper way to test a circuit, but this is a simple circuit, so we can cheat a little. This method works for the interior lights, too.

Also, to sort of answer one of your other questions, concerning the use of the meter: to use the meter to check the voltage to this circuit, page 9 of the Toyota manual is a little misleading. You always want the meter in series with the load if you are measuring current (amperage = A) (this is the last bullet point on page 3 of the Toyota Quick training guide). For voltage or continuity, it doesn't really matter as shown on pages 9-12; you can get the ground anywhere, as long as it's in the circuit. As a general rule, closer is better.

Think about electricity like water in a pipe. If you want to know how much water is flowing and how much pressure it has, you put those sensors in the pipe/tube/hose the water is flowing through and let the water flow through them. Connect your meter the same way.

Your test light here is sort of a meter. It will glow brighter, or not, depending on how much is flowing in the wire, until the point at which it can't handle the current and then it dies (actually the filaments melt and the circuit is no longer continuous - this is an open circuit).
 
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Run a wire from the battery to terminal on the horn.
If it makes noise then the horn works
If it doesn't make noise the horn is broken.
thanks tom. i just ran out and got my motorcycle leads and checked them and they both work. i guess the element in the light was using up the voltage or something...?

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I'm sorry for sticking my nose in here, but this is like watching a car crash in slow motion. And no, I didn't read through this entire thread. It's too damn painful and @Malleus deserves some sort of award for his patience.

The schematic should be the VERY FIRST THING you look at, not the last. All of the information is right in front of you.

Subdivide the circuit by removing the relay.
Do you get a constant +12 at pin 2 of the relay socket?
Do you get a good constant ground at pin 1 of the relay socket with the horn switch pressed?
If you jump pin 2-3 of the relay socket does the horn beep?

If you answered "no" to any of the above questions, you now know where in the circuit the problem lies.
If you answered "yes" to all the questions, then the issue is with the relay.
so test one i see 12V. i think i did it right.

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I'm sorry for sticking my nose in here, but this is like watching a car crash in slow motion. And no, I didn't read through this entire thread. It's too damn painful and @Malleus deserves some sort of award for his patience.

The schematic should be the VERY FIRST THING you look at, not the last. All of the information is right in front of you.

Subdivide the circuit by removing the relay.
Do you get a constant +12 at pin 2 of the relay socket?
Do you get a good constant ground at pin 1 of the relay socket with the horn switch pressed?
If you jump pin 2-3 of the relay socket does the horn beep?

If you answered "no" to any of the above questions, you now know where in the circuit the problem lies.
If you answered "yes" to all the questions, then the issue is with the relay.
horn beeps on jumpering 2/3.

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The schematic should be the VERY FIRST THING you look at, not the last. All of the information is right in front of you.

Subdivide the circuit by removing the relay.
Do you get a constant +12 at pin 2 of the relay socket?
Do you get a good constant ground at pin 1 of the relay socket with the horn switch pressed?
If you jump pin 2-3 of the relay socket does the horn beep?

If you answered "no" to any of the above questions, you now know where in the circuit the problem lies.
If you answered "yes" to all the questions, then the issue is with the relay.
what's this one please?
"Do you get a good constant ground at pin 1 of the relay socket with the horn switch pressed?"
POS probe into the #1 slot and alligator clip for the NEG probe to the battery ground?
then push the horn and see if i see 12V? because if that is the test i don't see 12V (could be doing it wrong of course).
at the same time with the relay in if i push on the horn i do hear it clearly click.

what i am thinking now is to try the same test at the two connectors at the horn (not exactly sure how to test this though except that i do have a sound function on this MM).

the other thing is i will bench test the relay tonight.
 
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The temperature here is now (in theory), above freezing, so I just did this on my 80, the same way you did in your photo. If the horn is good, it'll make noise. Mine are something over 85 dB, connected directly to the battery. Your power supply has to be at least 12VDC.

I'd recommend spraying some CRC plastic safe cleaner in both connectors (the wiring harness and horn) before you put it back together. I use this for all my connectors; a stiff brush won't hurt. The yellow part is plastic, so don't scrub too hard on it if you're using a metal brush.
thanks for everything. i am sort of learning and doing the practical problem solving at the same time so your help is really appreciated. i don't find electrical easy and i don't find doing just one or just the other works.
anyway pics for anyone lurking that is interested in this stuff. i guess some folks would frown on the rubbing alcohol for not being pure enough.
anyway if anyone knows how to open these connectors without breaking them i would go back in and take them fully apart. i just was able to sort of prop it open by pushing on the nub.
i also cleaned the spades with emery paper.

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Your bench setup looks correct. Check the voltage of the battery. If it's at least 12V, and the horn doesn't hurt your ears, the horn is defective.

If you want to cheat this circuit check do this: connect your meter to the positive terminal in the horn connector and the negative to the ground at the horn mount. You should see either a continuous circuit (Ohm setting) or about 12V (VDC setting) when the horn switch on the steering wheel is pressed. You can get away with this method for this circuit because it's simple and self contained. If you don't get a continuous/12VDC result, power's not getting to the horn. This is not the proper way to test a circuit, but this is a simple circuit, so we can cheat a little. This method works for the interior lights, too.

Also, to sort of answer one of your other questions, concerning the use of the meter: to use the meter to check the voltage to this circuit, page 9 of the Toyota manual is a little misleading. You always want the meter in series with the load if you are measuring current (amperage = A) (this is the last bullet point on page 3 of the Toyota Quick training guide). For voltage or continuity, it doesn't really matter as shown on pages 9-12; you can get the ground anywhere, as long as it's in the circuit. As a general rule, closer is better.

Think about electricity like water in a pipe. If you want to know how much water is flowing and how much pressure it has, you put those sensors in the pipe/tube/hose the water is flowing through and let the water flow through them. Connect your meter the same way.

Your test light here is sort of a meter. It will glow brighter, or not, depending on how much is flowing in the wire, until the point at which it can't handle the current and then it dies (actually the filaments melt and the circuit is no longer continuous - this is an open circuit).
thanks man.
what's the settings for testing the horn with the relay pulled and then also at each of the horns please?
meaning if i am doing it with someone i can stand at the MM but also if i try it myself i can put the sound for voltage on? or not?
i think it is POS to the hot spade (or pin) and DC V setting - and i am looking for 12V?

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thanks for everything. i am sort of learning and doing the practical problem solving at the same time so your help is really appreciated. i don't find electrical easy and i don't find doing just one or just the other works.
anyway pics for anyone lurking that is interested in this stuff. i guess some folks would frown on the rubbing alcohol for not being pure enough.
anyway if anyone knows how to open these connectors without breaking them i would go back in and take them fully apart. i just was able to sort of prop it open by pushing on the nub.
i also cleaned the spades with emery paper.

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See my post on CRC cleaner. Also, the proper method for opening the connectors and removing the terminals is in the Wiring Harness Repair Manual, in the Resources section. You'll find this helpful when you want to really clean the terminals and the interior cavities in the connector housings. I use an emery board to clean terminals, or emery cloth, whichever is closer to hand.

You really want to be careful what you use on the old plastic connector housings.
 
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thanks man.
what's the settings for testing the horn with the relay pulled and then also at each of the horns please?
meaning if i am doing it with someone i can stand at the MM but also if i try it myself i can put the sound for voltage on? or not?
i think it is POS to the hot spade (or pin) and DC V setting - and i am looking for 12V?

View attachment 2908738
You can't test the circuit if it's not complete. My "shortcut" was to save the trouble of tearing down the entire circuit looking for a problem. You can measure EITHER voltage OR resistance, with a complete circuit. If you measure either at the horn end of the circuit, and get good values when the horn switch is pressed, and get no sound, the horn is bad.

This is a quick check you can do without taking anything apart, before tearing into the steering wheel. Without oversimplifying testing in general, this circuit only has 3 components: the horn(s), the horn switch (at the steering wheel) and the relay. AFTER you test the circuit as installed and get 12VDC and/or resistance (a complete circuit) at the horn when the steering wheel is pressed, you would check (in this order)
each horn for operation, on a bench, with a 12VDC power source,
the relay, on a bench, with a 12VDC power source,
then the horn switch for continuity.

If all three check out, and you still have no working horn, you're not holding your mouth right.

You won't get a meter tone measuring voltage, only resistance. Of course, if you get a meter tone, you shouldn't hear it, because the horn would be louder. You could conceivably have an open circuit in the wiring somewhere, but it's not likely. I would only check that as a last resort.

Sometimes you have to wait 24 hours after applying a liberal amount of beer to the problem.
 

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