Starting a wiring project, got questions.

[Azrael]

Alright, after buying my 40 last week, I quickly realized that I would need to completely rewire. I downloaded the instruction PDF from Painless (even though I'll probably end up with an EZ Wiring harness), as well as the wiring diagram for the 40s, and have been meticulously going over them. I'm coming up a bit short on a few things, and hope you folks can help me out.

To help, I'm in a '72 with a 2F swap, and I'm sure the wirings been hacked up many times, so it isn't quite the same as the diagram.

First off, we'll start with these pictures:

First, what's this? It's on the firewall behind the clutch pedal. It's got six wires going in through the plug, but the only things I can find with that many wires attached on the diagram are the hazard switch (obviousley not this) and the trailer socket change over switch (Should be in the back, right?).



Also, I know that's a hazard or turn flasher above it, but where's the other?

This, on the firewall, opposite the above, is the voltage regulator, right?



For the front heater, the fan is this unit in the engine bay, and the unit under the dash is just a vent opening, right? Any idea which wire is which? (High/Low/Ground)




Also, I can't seem to find the Water temp sender, oil pressure sender, as well as the speed detector. In fact, on this diagram, I can't figure out where the whole assembly attached to the speed detector is.

Any ideas where I can tap in to the wiper motor wires without having to string new wire up through that?


Many thanks in advance!

[inkpot]

Howdy! I had a 72 many years ago, and everything looks original and correct , with one exception. In the second pic, the blue wire with the yellow boot may be an add on. On the heater, the wire NOT going thru the resistor is the ground. In the first pic, the gold colored box is the turn signals, and the black one is the 4 ways, I think. It's only been 25 years since I sold it. Good luck. John

[PigHeaded]

Originally Posted by Azrael

Alright, after buying my 40 last week, I quickly realized that I would need to completely rewire. I downloaded the instruction PDF from Painless (even though I'll probably end up with an EZ Wiring harness), as well as the wiring diagram for the 40s, and have been meticulously going over them. I'm coming up a bit short on a few things, and hope you folks can help me out.

To help, I'm in a '72 with a 2F swap, and I'm sure the wirings been hacked up many times, so it isn't quite the same as the diagram.

First off, we'll start with these pictures:

First, what's this? It's on the firewall behind the clutch pedal. It's got six wires going in through the plug, but the only things I can find with that many wires attached on the diagram are the hazard switch (obviousley not this) and the trailer socket change over switch (Should be in the back, right?).



Also, I know that's a hazard or turn flasher above it, but where's the other?

This is the EGR controller for Emissions.

Originally Posted by Azrael

This, on the firewall, opposite the above, is the voltage regulator, right?

Yes, that's the voltage regulator.

Originally Posted by Azrael

For the front heater, the fan is this unit in the engine bay, and the unit under the dash is just a vent opening, right? Any idea which wire is which? (High/Low/Ground)

The wiring diagram that I have for a '71 doesn't have wire colors for the heater blower, but as inkpot said, the one without the resistor would be the ground. I may just go put a meter on mine now, because you've got me curious.

Originally Posted by Azrael

Also, I can't seem to find the Water temp sender, oil pressure sender, as well as the speed detector. In fact, on this diagram, I can't figure out where the whole assembly attached to the speed detector is.

On mine, the water temp sender wire comes through a hole at the top of the motor in the center of the firewall. It's a Yellow wire with a green stripe. The Oil Pressure sender wire comes out right by the voltage regulator, and is a Yellow wire with a black stripe.

The speed detector is built into the speedometer on the combination meter.

Originally Posted by Azrael

Any ideas where I can tap in to the wiper motor wires without having to string new wire up through that?


Many thanks in advance!

[PigHeaded]

Ok, metered out the heater blower wires (but I didn't really need to meter them, as it was apparent once I got a closer look). White with a black stripe is Ground, Blue with a black stripe is Hi, Blue with a white stripe is Lo.

[Azrael]

Thanks. I'll go check those out today to see if I can follow what you're saying.

Originally Posted by inkpot

In the second pic, the blue wire with the yellow boot may be an add on.

That one runs to the electronic choke. The guy I bought it from ran added that one the day before I bought it.

[DSRTRDR]

it all looks original to me, agree with John about the extra wire on the voltage regulator, what for

white with black stripe is always ground

do not hack up the hazard/turn signal/brake light connections, you will need them in OEM configuration if you want to use Toyota switches, or you will need to reconstruct the connections when you rewire the truck

why not just reconstruct the damaged wiring ?

[Pin_Head]

What makes you think you need to replace the wiring?

Your wiring looks reasonably stock and intact, so it is almost always easier to just repair any problem circuits.

The electric choke wire is hooked up to the field terminal of the voltage regulator, which may cause problems for your alternator output. Maybe not; but it will affect the maximum power output. It would be better hooked up to the white wire with red stripe, which is key on power from the engine fuse.

[Azrael]

Originally Posted by Pin_Head

What makes you think you need to replace the wiring?

As of right now, I've got no lighting in back, and only headlights up front. Several switches and indicator lights on the dash don't work, and after trying to patch some of these up, I lost the ignition circuit just from shaking other wires in the process.

I'm sure if I spent the time, I could track these down, but it would mean tearing them all out anyway. There are many places I've found where someone had patched wiring by doing a half-assed job of just twisting the wires and taping them up.

I'd feel much better in the truck if it just had a fresh start at this point.

[Pin_Head]

Sounds like easy fixes. If you think that tearing it out and trying to install something generic that doesn't fit right is easier, it may end up being a hard and expensive lession.

[Azrael]

Well, I went out and played around today, and came to a few conclusions. I made temporary connections from the ignition switch to the starter and coil, which I suspected would be the problems, but it made no difference. I did, however buy a battery charger, since mine had died trying to get things to work earlier in the week (I did this before testing those wires). It still didn't start, but it didn't get a full charge yet. The starter did make some grinding noises, butit didn't turn over. I'm hoping after a full charge, it will start tomorrow. If not, I'll have to look into fixing/replacing the starter, and maybe replacing the battery.If I get it started, I'll need to test the alternator to make sure it's charging the battery properly.

Hopefully this is the problem so that I can just worry about the wiring to the rear lights and be done with it.

[PigHeaded]

One thing that I learned recently is that a good place to start is the fuse holder. I had several intermittant power issues, and found them to be caused by bad connections on the fuse block. Disconnect the battery, remove the fuse block, and check/clean all of the connections with scotch brite. Also remove the fuses (paying attention to which goes where, or do one at a time) and also clean the fuse clips with scotch brite. If any of the fuses feel loose, then carefully pinch the fuse clips with pliers to get more tension to hold the fuse. Once all cleaned up, put it back together.

Another big source of electrical gremlins is loose grounds. Check all ground wires where they attach to the frame/body. Clean up with sandpaper and make sure they are tight.

If your battery has enough juice to power the headlights, then it should be able to power the parking/turn signal/hazard/brake lights as well as the interior lighting. It may not have enough power to turn the starter though.

[PigHeaded]

I'm kinda' surprized that no one has made an OEM type Plug & Play wiring harness for these trucks. As popular as they are to restore, I would think that there would be a great market for a high quality wiring harness made using all OEM color codes and connectors. It could be sold as a complete kit, or in sections (such as the troublesome back half). It could also have options for additional circuits, and possibly plug & play adaptability for popular engine swaps such as TBI or Vortech.

I thought of trying to get all new connectors, and proper color coded wire and making my own, but you can usually only buy the wire in large spools (like 500' or 1000') to get anything but standard colors.

Another great upgrade would be watertight connectors (although then it wouldn't be compatible with OEM in sections without changing connectors). You could also switch the fuse block to a newer style, but try to keep the OEM location and mounting.

[Azrael]

Good call on the fuse box. I'll give that a try tomorrow before I test the new charge.

Originally Posted by PigHeaded

If your battery has enough juice to power the headlights, then it should be able to power the parking/turn signal/hazard/brake lights as well as the interior lighting. It may not have enough power to turn the starter though.

I know for certain that the back lights are a wiring issue. The driver's side was working fine when I bought it, but stopped when I tried some quick fixes to the other connections. All the bulbs back there are good, though.

[PigHeaded]

You could also check the wires on the back of the Ammeter. Hopefully they don't look like this:

[jimhendrixx]

You got some good ideas and a bit of work ahead of you. Best of luck my friend!

[Azrael]

Originally Posted by PigHeaded

You could also check the wires on the back of the Ammeter. Hopefully they don't look like this:

Everything on the back of the gauge cluster appears to be in good shape. When I try to crank it, I'm getting a load reading on there. I am, however, missing the temp/oil guages. A previous owner had aftermarket guages hooked up, that the last guy took off. Hopefully the wires are just hidden away somewhere under the dash.


Luckily, I went out to give it one last shot, and she started up with a little persuasion. Then the rear side markers magically started working. Hopefully that means the rest won't be hard to fix.

I think the battery will still need to be replaced. Ny suggestions on a good one that won't break the bank? Reading around, it sounds like the deep cycle marine battery that someone else put on there isn't the best choice.

[DSRTRDR]

Originally Posted by PigHeaded

One thing that I learned recently is that a good place to start is the fuse holder.

X2

that's where my first problem occurred (the second was trailer wiring and other hacks )

[DSRTRDR]

Originally Posted by Azrael

Reading around, it sounds like the deep cycle marine battery that someone else put on there isn't the best choice.

I have a deep cycle marine battery and love it

Excide Orbital, ~$200 with extended warranty