Wiring Nightmare (1 Viewer)

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If you're going to do that, use different color wires for each application. You might consider getting a trailer wiring kit. It comes in a grouping of 4 or 5 different wires with separate color coded wires. Each color is designated for its use. Rt, Lt, brake etc. If the lights act strangely like your turn signal wires both flashing is probably a grd issue. Turn signals and flashers use the same wire.
Good idea, but I already got 100' of red wire and I need to get this moving again. I'll just label the wire at the ends and get the correct colors once I am ready to do the whole thing correctly.
 
OK

I hooked it up.
Works better than before, but still getting the same issue as before: The blinkers don't work when the headlights are turned on. This is both front and rear blinkers.
Brakes work. Left and right turn signals work. Hazards work. (front and rear) Back-up lights work... but the moment I turn on the headlights, neither the turn signals nor the flashers/hazards work-front or rear. Lights just stay on steady.

I don't think the hookup of the rear lights are an issue, as this was happening before, but here's a drawing of how I have them connected:

IMG_0270.jpg

Thinking maybe swap the Brake (Green/White) connection with the Taillight (Green)? But that would just switch which fillament in the bulbs gets used for the particular selection.

Could this be an issue with the light switch?

This sucks, as I cannot drive at night.

Any ideas are appreciated.

Thanks.
 
Looks good. Yes that would just switch the filaments around... assuming that the bulb is the right way - can be forced in wrongly or the contact disk can get turned around.

The headlight causes them to go out. That's weird. I'd say that it probably due to corrosion at the fuse box and/or the hazard switch connector.

Disconnect the battery, and pull the fuse box out. Check all front and rear contacts - or photo it with your phone and maybe can see it
 
Looks good. Yes that would just switch the filaments around... assuming that the bulb is the right way - can be forced in wrongly or the contact disk can get turned around.

The headlight causes them to go out. That's weird. I'd say that it probably due to corrosion at the fuse box and/or the hazard switch connector.

Disconnect the battery, and pull the fuse box out. Check all front and rear contacts - or photo it with your phone and maybe can see it
Thanks. I'll check on that. Will try to do it a little later today and I'll let you know.
 
Oh boy! Looky what I found.....

What MESS!
So obviously there's rust on the fuses. That isn't a big deal. I can sort that out.
But the WIRING is all screwed up.
  • That thick red wire is spliced into two spots, but was cut and both ends are just there-with some electrical tape covering up the exposed ends.
  • The cylinder, which looks like the flasher solenoid thing (?) was connected to the green wire, but that wire broke off just from moving it.
  • There's a black wire also spliced in, and this one is also cut.
  • That box saying "12V20A 277" looks like some kind of relay.
I removed the red and black wires that were spliced in. ! could just clean and patch up what's there. ???

This had a Vintage Air unit, but that was removed first thing because it was a real hack job and was shredding belts. To give an idea of the professionalism of that install, when I removed the water hose, there was what looks like hair, mud, and pebbles inside.
IMG_0271.jpg
IMG_0272.jpg
IMG_0273.jpg
IMG_0274.jpg


More pics in a minute...
 
Whoosh, and down the rabbit hole we go.....

On a more serious note - it is absolutely worth taking the time to fix this - one circuit at a time, following the diagrams.
Not taking care of this could well burn up your truck. When you are not actively working on the truck, disconnect the battery to minimize the risk.

A multimeter and or test light are your friend here - nothing expensive is needed. And tape off every exposed wire. A short to ground on the White/blue can be a disaster - as this is a main current carrier.

@Coolerman has some great advice on how to clean the fuse panel.
 
Bingo!
That's where your problem is coming from.
Make each one of those connections good, and you should be back in business.

The fuse box looks to be generally in pretty good shape to be fair. It's just the wiring that has been fiddled with.

Just go one by one and make sure they're well connected and well insulated.
 
The dodgy looking red- black on the back of the fuse box should be the cigarette lighter and interior light - they often have accessories tapped into them like stereo or similar - I guess that's what happened here.

See picture below. Highlighted in blue... this looks like your glow plug cable. Normally there's a 'controller' between those two ring terminals, but it's been removed. No big deal but you'll need to bear in mind when you buy new glow plugs. It varies a lot of current so don't leave it uninsulated!

In yellow.. this is a bodged fix to get power to your turn signal. That wire should actually go to a green-black wire from the hazard switch. This 'fix' is probably because your hazard connector is corroded too - worth checking and fixing correctly.
Check for 12v on each of the green-red wires at that connector (below centre of the dash).

IMG_0272.jpg
 
Whoosh, and down the rabbit hole we go.....

On a more serious note - it is absolutely worth taking the time to fix this - one circuit at a time, following the diagrams.
Not taking care of this could well burn up your truck. When you are not actively working on the truck, disconnect the battery to minimize the risk.

A multimeter and or test light are your friend here - nothing expensive is needed. And tape off every exposed wire. A short to ground on the White/blue can be a disaster - as this is a main current carrier.

@Coolerman has some great advice on how to clean the fuse panel.
I have a multimeter and test light, so that's good. I'm gonna get on it tomorrow after mass. Wish I had my garage already! I'd work on it tonight!!
Thanks for the cleaning link!
 
The dodgy looking red- black on the back of the fuse box should be the cigarette lighter and interior light - they often have accessories tapped into them like stereo or similar - I guess that's what happened here.

See picture below. Highlighted in blue... this looks like your glow plug cable. Normally there's a 'controller' between those two ring terminals, but it's been removed. No big deal but you'll need to bear in mind when you buy new glow plugs. It varies a lot of current so don't leave it uninsulated!

In yellow.. this is a bodged fix to get power to your turn signal. That wire should actually go to a green-black wire from the hazard switch. This 'fix' is probably because your hazard connector is corroded too - worth checking and fixing correctly.
Check for 12v on each of the green-red wires at that connector (below centre of the dash).

View attachment 3467293
Thank you!
  • So is the cylindrical thing the hazard switch/flasher? It has three connection points, but I only saw two wires hooked to it, one of which broke off.
  • What's the rectangular box with the red, and White/Blue, wires?
  • Any idea of what glow plug controller to get, and where, for the glow plug cable?
 
Is this correct?


Gonna check about the flasher when I get home: the three wires-if I can make sense of the diagram.
 
Thank you!
  • So is the cylindrical thing the hazard switch/flasher? It has three connection points, but I only saw two wires hooked to it, one of which broke off.
  • What's the rectangular box with the red, and White/Blue, wires?
  • Any idea of what glow plug controller to get, and where, for the glow plug cable?
Yes, looks like the flasher unit but not the original 2pin one. Aftermarket ones are cheap so worth replacing whilst you're in there.
Not sure about the rectangle - anyone? Maybe a shunt for the ammeter??
 
Is this correct?


Gonna check about the flasher when I get home: the three wires-if I can make sense of the diagram.
That looks like the right thing but beware that there are 2 - one is 12v and one is 24v, however the manufactures seem to regularly confuse the part numbers. One has thicker coil wire than the other.

Are you sure that you don't already have one fitted in your dash (below the headlight switch)?

If you refit the controller then you might need to change your glow plugs to a lower voltage rating - there is a whole thread somewhere on plug voltages and controllers.
 
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Yes, looks like the flasher unit but not the original 2pin one. Aftermarket ones are cheap so worth replacing whilst you're in there.
Not sure about the rectangle - anyone? Maybe a shunt for the ammeter??
Thanks
I’ll have to look for the oem or repro flasher.
Maybe the dealer?
If anyone has a part number, please let me know.
 
That looks like the right thing but beware that there are 2 - one is 12v and one is 24v, however the manufactures seem to regularly confuse the part numbers. One has thicker coil wire than the other.

Are you sure that you don't already have one fitted in your dash (below the headlight switch)?

If you refit the controller then you might need to change your glow plugs to a lower voltage rating - there is a whole thread somewhere on plug voltages and controllers.
I don’t think there’s one under the dash but will look.
I was just reading that not having a controller can lead to white smoke at startup and some other issues.
I have a good deal of white smoke on startup, and also when driving (acceleration).
I will look for a diesel mechanic to check on the engine governor as well. Was told that it’s a “Dexel” and is still in business.
 
would the flasher/turn relay thing be the same as in a n FJ40?
Since it’s 12 Volt, seems like it should be.
 
Also, that rectangular box thing has a wire (white/blue) spliced to the same type wire going for the fuse box.
Any ideas?
IMG_0289.jpeg
 
Broken off wire at this 30A fuse connection.
I don’t see the wire it was connect to.

Only loose wire I see is the green one that was connected to the blinker solenoid.

Could this broken off spot be for the other wire to the flasher? Seems like 30 A is a lot though.

IMG_0306.jpeg
 
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