Builds Finally got my own...Meet BeBe

[gregnash]

Thanks J, much appreciated... Was just hoping that there was a shorter, cleaner way of doing it than going to the drivers side and then to the passenger side. Oh well, Mr. T did it with our trucks so guess there is really no worry in that. Question is that with that much cable running for power I am think that a minimum of 12ga wire is needed at those lengths. At this rate I might as well replace the damn antenna as well.

 

[TRAIL TAILOR]

Thanks J, much appreciated... Was just hoping that there was a shorter, cleaner way of doing it than going to the drivers side and then to the passenger side. Oh well, Mr. T did it with our trucks so guess there is really no worry in that. Question is that with that much cable running for power I am think that a minimum of 12ga wire is needed at those lengths. At this rate I might as well replace the damn antenna as well.

12 or 10 gauge is a good start. I know there is a length/amp draw formula to size wire.. I thought I had it, but can't find it.

J

 

[gregnash]

Ok may just bite the bullet and go with 10ga then to save myself some time.... Maybe one of the electrical guys like @Spook50 can lend a hand.

 

[gregnash]

Ok looking for some electrical help.....

Apparently I am a complete moron when it comes to electricity as I just don't quite get it yet. See I said yet because I believe that I need to see it in action to fully grasp what is going on.

Anyways, I have found out that somehow during the time I was cutting out the superfluous rats nest of wiring from the old cruise control module I somehow clipped the line that was serving as the 12v battery connection (which is weird because I did not cut any lines off from the battery connector).
Which means that right now I have ZERO power to my stereo harness from the "battery" line which I am assuming is the 12v hot lead.

Now I did have someone build me one of Eric's (@slcfj62) wiring harnesses, the ultimate with the two remaining openings at the bottom of the fuse box, and they did a good job I just need to install it. The install of that seems pretty straight forward but as towards adding accessories this is where I am lost completely....

On the bottom of my harness there are the wires for the two remaining open fuse blocks for accessories, the person that built if for me put in relays and a single 20amp fuse for each block. I don't plan on running anything like a CB, winch, etc anytime in the near future so I would like to just hook the stereo hot wire directly to it. Where I am confused is how I hook everything up as there are two red wires that come out of each block (area) and a single green. I am assuming that the green is probably a ground of some sort while the red are the hot leads. Now depending on which lead I pick will determine whether it is a constant hot or a switched hot. Is that correct???

Like I said I am a complete moron at this as I have never really dealt with electricity. Really don't feel like blowing up my harness, stereo, etc so that is why I am trying to figure this out now before I start dicking around with it.

Also, I went looking for wire and was only able to find 14ga low voltage, wire at the local shops in anything other than small foot lengths. When I looked at the wires (and held the stripers over it to somewhat measure) I came up with them being either 12ga or 14ga. Am I going to run into a problem with this?

 

[Granite Grinder]

I would check to see if those fuses are switched through the relays, that is how Erik wires his relay block to facilitate adding accessories like driving lights. I would take the time to add a fuse block, perhaps on the drivers side kick panel, that is fed by a constant 12v hot. Then if you ever need to add items like a CB, Ham or even just a hot lighter plug for iPod/ iPhones you'll have a convenient place to tap

 

[gregnash]

Ok thanks for the information @Granite Grinder. I will take a look around for something to do here. I was hoping that I would be able to just wire it directly to this and not worry about adding another auxiliary box anywhere but I understand what you are saying.

 

[Slow Left]

Greg, have you got a copy of the wiring diagram for your 1985 FJ60? The Landcruiser Repair Manual for 1980 Chassis-Body should include a wiring diagram in the back. (EDIT: THERE IS ALSO AN UPDATED SUPPLEMENT FOR THE 1985 AND LATER FJ60s) If you don't already have a copy I can upload an image of the diagram (the Manual itself is too large to upload here).

How are you taking measurements of the circuit(s)? In other words, what make/model multi-meter are you using, what is it capable of measuring (Volts, Ohms)?

How about the local Landcruiser club...anyone there you can team up with to run the trouble shooting?

 

[gregnash]

I have all the digital manuals but just have not had a chance to look through them to see where the wiring diagram was. I do have a Multi-meter but do not know the brand/model off-hand (just one purchased from Lowe's).

With checking to see if I have any power I am simply using a test light to see if I actually have an power going to the battery or not, I have posted something in my club forum so we will see if the guys respond.

 

[Slow Left]

Alright.

The vehicle's electrical system is DC (Direct Current) - as opposed to AC (Alternating Current) that you see in homes.
DC systems obey Ohm's Law:

V = IR

where V is Volts (measured in Volts), I is current (measured in Amperes) and R is resistance (measured in Ohms)

To build an intuition around what this relation means, think of water flowing down a hill.
The higher the hill, the more potential energy to water will have at the top of the hill (Voltage - the higher the voltage, the more potential energy)
The wider the channel in which the water can flow, the lower the resistance and vice versa (Resistance - analagous to the wire gauge - the higher the AWG (American Wire Gauge - for us Yanks...) number, the skinnier the wire the more resistance to flow than a thicker wire for the same applied voltage).
The more water flows, the greater the current (Current in Amperes).

you can also write Ohm's Law:

V/R = I
or
V/I = R

So for the 12V system, selecting the correct gauge wire is important because if the wire is too small (high AGW number), R increases and I decreases (because V stays the same at 12V). If AGW is too small, R becomes too large and the wire becomes hot - potential fire hazard.
On the flip side, if the wire is too wide in diameter (low AGW number), R decreases and I increases. If I increases too much, then it can send too much current to the component and overwhelm the circuits on the component with current.
So fuses are used to prevent the circuit from reaching these extremes because the fuse is rated to blow at a lower threshold and break the circuit in a sacrificial act of protection.

To test whether a wire is good (able to freely conduct through it), you can do a continuity test by setting the multimeter to measure Ohms (to measure Resistance) and then attach one lead from the meter at one end of the wire and the other lead to the other wire end. If the wire is conducting properly, the reading should be on the order of tens of Ohms. You can also test fuses this way to make sure they are still good.
If there is a switch somewhere along the wire, and the switch is off, then the meter should show a Resistance value of infinity (open circuit...so it is not conducting, so there is a very large Resistance - the 'air gap' of the open switch). If you turn the switch to on, and both the switch and wire are working properly, then you should see Resistance value on the order of tens of Ohms again.

To test whether a wire is 'hot' or seeing 12V from the battery, set the multimeter to V and connect the red (+) lead from the voltmeter to the wire and ground the black (-) lead from the multimeter (any screw or metal on the dash or frame will do). If it is hot, it should read 12V. If there is a switch between the battery and the end of the wire you are testing, then with the switch off, it should read 0V and with the switch on it should read 12V.

With those two types of measurements, you should be able to work step by step through most circuits on the vehicle to make sure that all paths (wires) and switches are working correctly.

Probably want to stay away from taking measurements from the charging system (alternator charging the battery) - high current = danger - and the High Voltage Ignition (coil supplying thousands of volts to the spark plugs).

 

[Slow Left]

So for the radio, most modern radios have both a constant 12V wire connection (sees 12V from the battery even when the car is 'off' and ignition switch is 'off' - this is for storing memory for all those preset values like station selection etc.) and a second 12V, power lead through the ignition switch that will only power the radio on when the key in the ignition switch is on (in and turned to ACC or on).

Often time, figuring out which one is which is just a process of elimination, testing the different scenarios. If you know that one lead is supposed to be 12V all the time, then test each wire with the multi-meter set to Volt and the black (-) lead from the meter grounded until you find the one that gives you a 12V reading even with the key out of the ignition. Then find the one that will only give you 12V reading with the key in and on ACC, and this one is the one that will power the radio.

But it seems to me that, given the other electrical issues that you had with the fusible link etc. that something else might be going on.

Right before the issues with the fusible link, were there any other electrical symptoms/indicators? Or had you been doing electrical work on the vehicle right before the fusible link problem came up?

I'm trying to see the order of the events to try and understand if there might be cause and effect. For instance, you mentioned that cut out some wires on the cruise control...when was that in the timeline of things?

 

[dirtEJohnson]

Well spoken Slow Left.

I recently threw a head unit in mine and if I recall correctly I used the existing (factory) audio leads for 12v switched (W/R) and ground (B). I used the accessory lamp connector above the RH kick panel for B+ since I don't have one of those nifty lights.

 

[gregnash]

Thanks for the explanation SlowLeft that does help some.

As to answer you question directly, no there were no symptoms and no I had not done any electrical work prior to this issue. The stereo was installed over a year ago and has worked fine until this point.

When all this happened I started going through the wires that were connected to the plug for the cruise control (removed the module a while after getting the truck and figuring out what it was). When I had the issue with the fusible link there were multiple wires that I had cut off previously with no issues and some others that were cut off by the PO (he did not install the cc, it was the owner before and he had not idea what the box was). Now that I am thinking about it there were two wires that went all the way around to the passenger side that connected to the ignitor and somewhere else (can't remember now) that I disconnected and removed. When I started looking at all the wires on the back of the cc plug I found the wire that was still connected (and marked as 12v) to the harness and left it and one other wire alone. From there that is when this issue started which makes be believe that I removed the wire somewhere in that mix.

The remainder of the wires that were attached to the cc plug were all disconnected except for two that I can remember and one was a loop to itself and the other was linked to a screw on the steering console. This was seriously a CF job for the install of this cc and there are two wires that I have absolutely no clue as to what they are connecting to and do not want to cut them for fear of killing something in the ignition (they are out of the way and hard to see on the back side of the gauges and steering console).

Because of all this, I wanted to just go ahead and run new wire for the stereo to make things "cleaner". Seems like one of the wires that I cut (thinking the one that was looped into itself) was a power supply wire for the hot 12v.

For the ultimate harness, if I am understanding your testing methodology correctly I can basically install and then individually test the leads with the truck switched off to see which one is supplying 12v and from there I will be able to run the hot lead to the stereo in the cabin. However, with the pending possibility of other interior accessories you are saying that it would be easier to run a small fusebox in the cabin and run the "supply" leads from my ultimate harness to that, then from there I can run the hot lead to the stereo and whatever other accessories I would need.

With regards to the wiring, should I just go ahead and return the 14ga? I was looking for 12ga but I need a decent length of it and I cannot find anything that is more than a couple feet (at least not at Lowe's or Home Depot).

 

[TallCanDan]

Only thing I can think of to source fatter/ longer wire would be a car audio shop...

 

[Slow Left]

Here is an image of the wiring diagram from the Landcruiser Chasis-Body 1980 Repair Manual. See attached.

EDIT: I just noticed that this image quality sucks. When I grabbed it out of the .pdf and saved it as a .jpg, before I uploaded it, I checked to make sure that the resolution was good enough to zoom in and read the diagram.
But uploading it must have compressed the image and compromised the resolution.

If you need a copy of the diagram, let me know and I'll give it another shot, but if I recall, you mentioned that you already have a soft copy...

 

[Slow Left]

It seems like there are three issues:
1) the fusible links
2) the cruise control
3) the radio that was working but now isn't

They might or might not be related, it is hard to tell from here. I would try to resolve those issues first before slicing in additional component (like breaker boxes or the like), make it simpler first by trying to get it back to proper order before then add in robustness once you have figured out what is what.

For the fusible links, it seems like your fix worked (since the truck is running), so maybe come back to that later and double check it.

For the cruise control, it is going to take some trouble shooting to figure out what that guy did and how to restore it back to the original layout (in the wiring diagram).

For the radio, you can test it as is to try to identify what the problem is, since it was working before.
Do you have easy access to the harness that clips into the back of the radio? You should be able to unclip it and all the wires (most of them are speaker wires) that lead into the radio should come out in one shot.
A manual for the radio (either hard copy or on line) should tell you which wire is supposed to be: a speaker wire, 12V+ (constant - for 'memory' of presets), 12V+ (switched through the ACC - this is power for running the radio) and ground.
Or you can test.
With the engine off and ACC off, using the Volt option on the multimeter, ground the black (-) to a metal on the dash or frame etc and touch the red (+) lead to each of the wires leads that you know are not speaker wire leads.
The one that shows 12V is the constant one (for preset memory).
Now turn the key so that the ignition is on ACC, and test the other two wires. The one that now shows 12V (but didn't with ACC off) if the switched power source.
The remaining wire should be ground.
(You can also use that tool that has the light bulb - looks kinda like a sharp tip screwdriver with a wire hanging off the back?? Just ground that wire, and when you touch the metal tip to a hot 12V+ wire lead, then current will flow towards ground, passing through the light bulb and the light bulb will shine)

Now if you run this test on the radio, and find only one (or maybe even none) wire that gives you 12V+ (is it the one that is switched or constant 12V???) then there is a break in the circuit between the batter and the radio (and maybe through the switch, if it is the one that is switched).
Based on that information, you can proceed to find out if you can either repair that connection or replace that connection with a new wire.

If you look at the wiring diagram (and also refer to DirtEJohnson's post above), the original circuit for the radio from the manufacturer had only one 12V+ wire, and it was the switched one. The stock radio didn't need the constant 12V+ because it presumably had mechanical presets that worked as memory for the station presets.

Look on the upper left side of the wiring diagram.
You will see the battery, then you will see the three fusible links coming off the battery.
The center link of the three, labeled 'B', leads to the ignition switch.
When the ignition switch is in 'ACC', the 'LR' wire that leads out becomes hot.
If you follow the LR wire across the top of the wiring diagram over to the right side, you see it splits.
It powers both the cigarette lighter (through a 15 Amp fuse) and the radio (through a 5 Amp fuse).
It looks like the 'LY' wire that leads from the other side of the 5 Amp fuse to the radio is the factory 12V+ switched wire to the radio, and is probably 'Light Yellow' in color.
You can confirm it is working using the test above.
Off the radio there is a 'WB' wire that runs to ground. It appears to be the factory ground wire for the radio, and is probably 'White Black' in color.

Now, since your radio is not the factory radio, and needs a constant 12V+, there should be another hot (but not switched wire) that is attached to the harness.
Depending on who installed the radio, that 12V+ constant wire could be:
1) a dedicated wire that leads directly to the battery terminal (this is what I did...fished it through the firewall on the passenger side where the antenna goes through and connected it to the positive battery terminal)
2) tapped into another 12V+ wire in the harness that is connected back to the battery through a factory circuit

The trick is going to be, if this 12V+ constant source isn't working, figuring out how it connects back to the battery.
But first figure out which leads are working correctly, which wire is 12V+ switched versus constant, and which is ground.

 

[Slow Left]

To answer you question about which gauge wire to use...it depends.

You can either:
1) measure the gauge used in other wires on that circuit and use that same gauge (there are simple tools that can do this - google 'measure wire gauge)
2) calculate based on the demands of the circuit

The device (radio in this case) draws a required amount of current (it's called Load and is measured in Amperes).
The voltage from the battery is fixed (12V).
The wire delivers the current from the battery to the radio, but is a source of resistance.

Remember V = IR

The problem is, that since the radio will try to draw as much current as it needs from the battery source, it can't draw more than the wire (Resistance) will allow.
So a 24 AGW (just an example, not necessarily the gauge you need) is really skinny, and might resist (prevent) the required flow of current that the load (radio) is trying to draw from the battery. That's when the wire gets really hot, melts the insulation around it and grounds itself, shorting the cirucuit.
On the other hand, a 2 AGW (again, just and example) is a really fat wire, and offers considerably less resistance to the flow of current. In this case, the load might be permitted to draw more current than it should and result in overloading the circuits within the device itself, killing it.

Attached is a .pdf that shows you how wire gauge is selected base on Load.

 

[gregnash]

Thank you again for the responses @Slow Left, again much appreciated..
Just for reference, and a little more info on the fusible links, here is the thread I did for that issue.

Luckily I was diligent enough to mark all the wires and test them before I installed the stereo so I know what is what in there. I will use my multi-meter tonight to test the ACC and 12V Battery to ensure that everything is working as it should according to your testing methodology. I will also attempt to take some pics of what is remaining of the cruise control module.

 

[Slow Left]

Alright.
For the problem solving on the cruise control issue, comparing the color coding from the wiring diagrams to the wires you cut in order to remove the 'module' will help in understanding the problem.
If you can identify which factory wires this 'module' tapped into, that will help in understanding the current situation of the circuits and how to approach testing whether they are functioning properly.

 

[gregnash]

Ok well I went back through the wiring with the multi-meter and everything was working as it should be. Even went as far as to check all the connections and make sure I didnt see a break or bad kink somewhere. Sure enough everything was fine and I plug the stereo in and she powered right up. I am stumped unless there is a bad connection somewhere that I couldn't get to or see and by pulling on the wires some when I was testing I was able to reset the connection.

 

[Slow Left]

Huh. Well, that's good that it works and that all the tests gave the right results.

Since the power to the radio comes through the 12V+ with the ACC switch, and if there is some gremlin in that circuit, there it could be something like a wire occasionally grounding, or a fuse (either the 5 Amp fuse in the box, or the fusible link between the battery and the ACC switch) making intermittent contact.
So if the power goes again, you can repeat the Voltage test, working your way back methodically from the 12V+ input to the radio, along the circuit, testing both sides of the component (wire, switch, fuse, etc.) until you see the 12V+, then you've identified the culprit.

Same thing goes for rechecking the fusible links. Working your way back towards the battery, you should see 12V+ on the far side of each of those links, and their components (depending if the switch is open/closed).

How about this cruise control issue? Any luck identifying the wires (matching their color to the wiring diagram or following them to see where they lead)?