Riddle me this - electrical gurus

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joyRidaz

joyRidaz

10 Year
Joined
Mar 11, 2013
Threads
57
Messages
1,170
ok ive had several head scratching years of on-again and off again half-heartedly trying to sort out my horn troubles on the fj60

I'm due for an annual inspection/registration and figured I'd give it my annual attempt before crossing my fingers and hoping the inspector looks the other way.

Over the years I've attempted the usual mud-approved solutions:
- 22 brass casing
- new brass horn spring-loaded "stick" , can't remember the official name
-new brass circle ring inside the steering column
- cleaned all contact points and tried dialectic grease
- washers under the various horn buttons, contacts etc
- fuses
- new aftermarket horns

After all that I still was left with an I working horn 90% of the time, luckily it works when I really need it (LR inspection, occasionally when someone cuts me off)

Over the weekend I dove into the wiring... and I'm baffled, I have found a weird "hack" that I can't explain and I'm terrible at electrical and am intimidated.

The hack is, if I disconnect one of the two wire,either one, on the drivers side horn then it works. Doing the same on the passenger side makes them inoperable.

Having both plugged in on the DS makes it inoperable. Having both unplugged makes both DS and ps horns inoperable.

Switching the wires doesn't seem to impact it, as long as one is unplugged.. ,as soon as two wires are plugged in then it doesn't work.

What could it be? Grounding? Seems so bizarre

The good news is I'll pass inspection but I hate being dumb so must get to the bottom of this.

Any help or hints appreciated!
 
If I'm reading the description correctly it sounds like the coil in the DS horn is gone. Sorry, I changed my horns a couple/few years ago and did not keep the old ones.
 
If it makes you feel any better, I wire a new horn circuit on most every build I do. It's a simple circuit. The wheel side of the circuit touches ground and poof horn works. Power-fuse-relay-horns-ground. power-switch-relay-ground (horn button).
 
@Rice - I failed to mention that switching the DS and PS horns doesn't change the situation, nor does swapping back in the oem horns (which I luckily saved)

@NCFJ - thanks for the tip, I'll need to do some searching to find one of those circuits you mentioned.

Would "disconnecting one wire" to fix the problem lead us to believe it's a short or a bad ground?
 
@joyRidaz, you build this circuit from scratch. You already have the horns and the switch (horn button). All you need is power for the horn and the switch. I avoid changing the OEM harness whenever possible, so rather than mess with existing circuits i just build a new one, stand alone from the OEM harness. In this case the horn button itself is used, it's the switch.
 
joyRidaz said:
@Rice - I failed to mention that switching the DS and PS horns doesn't change the situation, nor does swapping back in the oem horns (which I luckily saved)

@NCFJ - thanks for the tip, I'll need to do some searching to find one of those circuits you mentioned.

Would "disconnecting one wire" to fix the problem lead us to believe it's a short or a bad ground?
Click to expand...

Odd question .... How well are the brake lights (not tail lights) operating? Weak? Nice and bright? It does not say so in the diagram but I believe the feed for the horn (from the fuse block) is the same as the brake lights.


1978 FJ40.gif


A relay fed horn is a very easy mod to make. NAPA Part # AR274 is a nice relay for this job because it has 2 "87" posts which are the "load" posts going to the horns.



horn relay.webp
 
Solved that problem, new horns, new circuit and new compressor. Yes, it gets people attention!

DSCN0285.webp
DSCN0287.webp
 
I'll check the brake lights tonight. Not sure if it's related but my parking brake indicator light never fully turns off. It gets fairly dim once it's not engaged and gets bright once it's engaged. Figured I should mention that since you mentioned the brake lights.

Rice said:
Odd question .... How well are the brake lights (not tail lights) operating? Weak? Nice and bright? It does not say so in the diagram but I believe the feed for the horn (from the fuse block) is the same as the brake lights.


View attachment 1434475

A relay fed horn is a very easy mod to make. NAPA Part # AR274 is a nice relay for this job because it has 2 "87" posts which are the "load" posts going to the horns.



View attachment 1434476
Click to expand...
 
Oh boy, this saga took a bad detour. Likely related to my horn hacking last weekend.

Yesterday while driving to/from concord, I watched my battery fully drain. When I left the rig started right up, horn worked great(only one wire connected on DS , other wire electrical taped).

After about fifteen mins of driving in town, started noticing a drop in voltage. Was jamming with radio loud(with amp) and iPhone plugged into cig lighter. Then after twenty mins of highway driving it really was low, from like 12 to 9ish amps. At this point I turned off radio, unplugged iPhone, and removed horn fuse... thinking maybe it was a short.

On the way home it flatlined even further. Luckily made it to my driveway. Where she is resting. I can jump it, and the voltage still drops while running even with electronics off(radio, lights etc)

I've been frantically trying to get smart enough to even pretend to try to diagnose. My initial hunch is bad alternator, connections to alternator, or diaode.

FYI battery is brand new.

Keep ya posted. Gonna try to charge battery, cleanup connections (maybe blocking connection to recharge?), play around with removing fuses to see what's using voltage, then try to test alternator (remove positive battery cable while running and test voltage). Not sure but also thinking I somehow need to test for bad wires between alternator and battery...

Anyone have convictions on this plan? Truck has a Toyota sensor alternator that was on there when I bought it, currently at 242k not sure if orig.
 
Plan is not bad. A fast easy test is to get a voltage reading at batt before starting and then with it running. If voltage with engine running is below what it was with engine off then we know there is no charging. That points to the alt or to the voltage regulator. The VR is a common fail item and will need testing. I believe you should find it on firewall under the brake booster.
 
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So from my interweb research and visual inspection, on my 84 fj60 it looks like the voltage regulator is built into the alternator.

When it's running and I unplug the negative cable it immediately dies.

My crummy HF ampmeter just died so will need to get the before after readings once I replace it.

Is it safe to say I've pinpointed that it's the alternator? With the neg battery cable test?
 
I agree with your statement in general. I can't even be mad at the broken ampmeter since it was a freebie.
 
Sorry ... I did not realize it was an 84. Is beginning to look like alternator then. Time for an autozone trip ... they can test it for you.
 
I'm happy and somewhat embarrassed to say that the lack of charging was likely due to a faulty fuse. Was swapping around fuses while diagnosising the weak horn syndrome and must have swapped in a bad fuse while trying to correct line up the right amperage to what the truck diagram requires.

While playing around I am starting to wonder why the PO had such mismatching amperage to what is listed on the diagram. There's quite a bit of mods going on, and I hope I don't mess up whatever hacks are there... aftermarket radio+amp, off-road lights, inverter, cb, several mysterious switches and wires . I even think there is wiring for a previous dual battery set up.

Generally speaking, it seems there were several empty spots on the fuse panel, and lots of incorrect amperage fuses versus the fuse diagram.

Oh well seems all is good now. Was really hoping putting a fuse in the a/c slot would give me a gust of cold air but sadly still blows warm.

Still looks like my voltage isn't as high as I remember on the cluster, but no hard facts, just fuzzy memory. @JohnVee and I will try to get some readings later this week.
 
joyRidaz said:
I'm happy and somewhat embarrassed to say that the lack of charging was likely due to a faulty fuse. Was swapping around fuses while diagnosising the weak horn syndrome and must have swapped in a bad fuse while trying to correct line up the right amperage to what the truck diagram requires.
Click to expand...
Don't feel bad, I hunted down new headlight switches for my 40 when it turned out to be a faulty fuse. Wasn't blown, but when I pulled it out, the end popped off... Bought not one, but TWO, replacement headlight switches and these things aren't cheap or easy to find! I've been pretty ashamed to admit it, but it was almost a year ago. C'est la vie...
 
Don't feel bad Jeremy, Doctors get to "practice" medicine, you were just practicing mechanics. :)

All kidding aside, electric issues will drive anyone over the edge. Most of the trucks I see have almost 30 years of people wiring all kinds of things up to the OEM system. At this point, anything I add to a truck has as little or no contact with the OEM wiring as possible.
 
Almost forgot to mention the good part... while switching around fuses to match the correct amperage I think I may have partially fixed the orig horn issue. Now the left most horn button beeps even with both of the wires attached... the other two buttons are still a bit hit or miss but hopefully good enough for inspection. I'm wondering if maybe the wrong fuse amperage rating was restricing the voltage to the horn and making it not fully fire

Now I'll shift my focus back to the forty, which also has a unique problem caused by me being a bonehead and putting the battery cables on backwards. Fried something. Swapping in a new fusible link and going to buy some more 10amp fuses to replace the engine one I blew... once that's sorted I'll then move to the water pump that seems to be leaking pretty heavily. The list never ends
 
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