74 Wiring questions (1 Viewer)

[musthave]

Working on getting my sons FJ40 on the road. Having issues figuring out wiring.

Original harness. I have the diagrams but not making sense.

Wasn't getting signal from ignition to starter on b/w wire. Ran one from the plug directly and it works now.

When I pull the light switch the speedometer lights up on the right side.

I have fender lights.

I have no headlights, fuse is good.

I have no turn signals, fuse is good.

On rear I stripped all the botched wiring and have 5 wires on right, left, center. Have no +12v on the r/w with the lights turned on.

Looks like the b/y from ignition controls power to turn signals?

I have no flasher under dash by the fuse box. I have the two wire plug. What do I need there?

There's a 3 prong box on the ps fender that I thought was the flasher but ?

Under steering column theres a butt connector next to multi wire plug with a g/w wire, what does it go to?

Need help for sure.

 

[45Dougal]

Sounds like you're making a good start. Have you got the wiring diagram? (All linked online here somewhere).

 

[Ming89FJ62]

Check @Coolerman web site for a schematic

 

[musthave]

I've got the diagrams, but things like the wire under the column don't show up there. So I'm lost.

The flasher assembly is on the diagram but doesn't say where it's located. I think by fusebox but not sure.

 

[V8FJ4078]

Flasher should be the 2 wire plug near the fuse box. The relay under the hood I believe is for the the horn.

 

[musthave]

Flasher should be the 2 wire plug near the fuse box. The relay under the hood I believe is for the the horn.

G/w and g/b are by fuse box and are for flasher. Still available?

The relay under hood on p/side looks like this.

 

[badsamaritan]

be sure you are using a diagram from a FSM and not a laminated one you get online. Those leave a lot of detail out in my opinion. I'd open up some of those connectors carefully and take look inside, could be all kinds of gunk in there. If you have ones that are crumbling, the Yazaki connectors are sold online and you can get a replacement. I had to go through several of mine, de-pin them from the connector and then replace the male/female spade terminals and put it in a new housing. Slowly, a lot of the issues started going away.

 

[musthave]

So the plastic connectors themselves, take apart and clean? Usually replace? How do the wires come out of the back? Pointed object?

 

[Sky King]

Something I have found resurrecting old trucks and motorcycles is to find all the grounding points for the harness and clean the connections I can't tell you how many times I've corrected circuit problems due to bad grounds.

 

[bikersmurf]

Never underestimate the importance of a ground…

Never underestimate the importance of a ground

I drove my truck for the first time in too long. I'd swear I had electrical gremlins if I didn't know the source of the problem. My windshield wipers stop working when I step on the brakes, hit a bump, or turn a corner. The front turn signals also light up when Braking. The hazards also do...

forum.ih8mud.com

 

[V8FJ4078]

G/w and g/b are by fuse box and are for flasher. Still available?

The relay under hood on p/side looks like this.

View attachment 3394574

Yes, those are the wires for the flasher. Not sure on availability, however coolerman sells one that would work for LED lights. I used it since I modified my turn signal circuit.
The other is the horn relay.
They make a tool to push in and release the tab that holds the terminal in the plastic for the 6.3 terminals. I bought one at jegs and I got another better one at Tools - Vintage Connections - http://vintageconnections.com/Products/Tools
There is a little area to slip that in while pushing the wire in, push the the tool then pull the wire and terminal out.
Some can be challenging to get out I found after remaking my entire harness.

 

[45Dougal]

Working on getting my sons FJ40 on the road. Having issues figuring out wiring.

Original harness. I have the diagrams but not making sense.

Wasn't getting signal from ignition to starter on b/w wire. Ran one from the plug directly and it works now.

I'd guess corrosion on the ignition switch connector block was the problem for this one.

When I pull the light switch the speedometer lights up on the right side.

That tells you that the switch is working correctly for the side lights at least - you probably have a blown or missing bulb on the left side of the cluster.

I have fender lights.

See above.

I have no headlights, fuse is good.

Try unplugging the switch and reseating the connector with a squirt of wd40. You can reach it under the dash but it's tricky.
Could be dirty switch contacts or more likely corroded connector - especially if it rains inside your truck.

I have no turn signals, fuse is good.

Check you have power both sides of the fuse. Appearance is deceptive.
Check you have power to both green-red wires at the hazard connector (with ign on). Clean corrosion on the hazard connector (due to rain from the centre vent).

On rear I stripped all the botched wiring and have 5 wires on right, left, center. Have no +12v on the r/w with the lights turned on.

Your front side lights work, so you should have power for tail lights. Trace the cable from the back upto the bulkhead.

Looks like the b/y from ignition controls power to turn signals?

BY feeds the turn fuse. If you have power at the turn fuse then you need to work down not up.

I have no flasher under dash by the fuse box. I have the two wire plug. What do I need there?

There is another unrelated connector there that is definitely not the flasher so be careful.
Everything you need can be found at the hazard connector above the heater.

There's a 3 prong box on the ps fender that I thought was the flasher but ?

Horn relay?

Under steering column theres a butt connector next to multi wire plug with a g/w wire, what does it go to?

I think it's unused on mine

Need help for sure.

View attachment 3394502

 

[musthave]

I'd guess corrosion on the ignition switch connector block was the problem for this one.

That tells you that the switch is working correctly for the side lights at least - you probably have a blown or missing bulb on the left side of the cluster.


See above.

Try unplugging the switch and reseating the connector with a squirt of wd40. You can reach it under the dash but it's tricky.
Could be dirty switch contacts or more likely corroded connector - especially if it rains inside your truck.

Check you have power both sides of the fuse. Appearance is deceptive.
Check you have power to both green-red wires at the hazard connector (with ign on). Clean corrosion on the hazard connector (due to rain from the centre vent).

Your front side lights work, so you should have power for tail lights. Trace the cable from the back upto the bulkhead.

BY feeds the turn fuse. If you have power at the turn fuse then you need to work down not up.

There is another unrelated connector there that is definitely not the flasher so be careful.
Everything you need can be found at the hazard connector above the heater.

Horn relay?

I think it's unused on mine

@45Dougal Thank you! I'm a lot further along.

Cleaned connectors under steering column and where the harness connects to rear harness.

Headlights work
Fender lights work
Side lights work

Installed new oem flasher.
I get a right and left directional on the fender lights but it's a fast blink. Not sure why. Maybe because no rear turn signals are connected? Any suggestions?

Once I figure out directional signals I'll move to the rear.

@V8FJ4078 Great suggestions. I don't have a good terminal pick but was able to use a pick of sorts to clean several.

 

[South Texas 97]

Yes, I believe you are correct. The blinker needs the full load of all indicators bulbs to function correctly. Rapid blink normally means one or more bulbs are burned out.