m1008 no head lights, horn, brake lights or black out lights

[gmjunky87]

sorry if this is redundant. started truck. no headlight, signals, brake lights, horn. made sure black out switches were in proper place. tried to turn black out lights on, nothing. checked head light fuse, it's fine (checked fuse with test light). unplugged black out switches and bypassed the switch. still nothing. not sure what else it could be.

 

[jcollings]

Did you check your firewall main feed ? or fusible link, possibly bad

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[mike634]

I had the same problem last year. The fuse block where the 30 amp fuse is melted. Fuse was fine but the wire was toast.

 

[jcollings]

Yeah that fuse and block takes a beating with all the load for the 12 V circuit. Definitely something to watch I'm debating whether to change my block/rewire or not, Is work in progress.

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[jcollings]

Hopefully GMjunkie87 gets his problem resolved.

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[gmjunky87]

I checked the main junction block on the firewall, it's past the fusible link. I'll have to take the junction apart at the firewall I guess. It seems like it would be something related to the blackout lights that's why I disconnected the plugs on the switches and made two jumper wires for the service light switch. I'm just stumped because I have power on either side of the fuse for the headlight

 

[jcollings]

So the junction block you have 12 V going into it and 12 V coming out going through the firewall to your fuse block?

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[gmjunky87]

Yes 12v going out also.
glow plug system works. Voltmeter on dash has never worked. One of the gen lights doesn't work but it's been that way a while ,(i shorter the fusible link once and prob burned out the bulb, I just charge the back battery)

When you turn the key on wait light, oil light, other gen light, water in fuel light come on and go off like normal.

I don't have access to the truck right now but I think I'll take the front battery out and check the wiring (I've been having rodents, truck doesnt get driven often) also start taking apart the bulk head to the firewall apart to clean it. I suck at reading wiring schematics but from older posts I've read i know a lot go through the head light circuit but it's acting like I have the service light switch off even though I have it bypassed.

Also I installed led headlights about 5 years ago to take some load off that circuit.

 

[jcollings]

LED, Those usually have some kind of driver set up which modifies the whole headlight system correct

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[jcollings]

You have this

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[jcollings]

This to

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[gmjunky87]

LED, Those usually have some kind of driver set up which modifies the whole headlight system correct

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The led lights didn't take any modification, they were plug and play. I still have the original square fuel filter with all the wiring for the baseplate if that's what you're referring to. Thanks

 

[jcollings]

I've seen some LED lights that are required drivers and different type of hook up in wiring.

I still have the square fuel filter myself

I hope you get it. Good luck

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[gmjunky87]

Thanks again, once I get to the truck I'll try to follow the schematics you sent

 

[WWRD99]

Thanks again, once I get to the truck I'll try to follow the schematics you sent

I go up towards Halifax a good bit if you can't find it. Probably next weekend.

 

[gmjunky87]

I go up towards Halifax a good bit if you can't find it. Probably next weekend.

ah ok thanks! Im still outta town unfortunately

 

[gmjunky87]

Well, I'm an idiot! after spending hours cleaning grounds, the bus bars, bulk head connection, having the dash apart checking the blackout light relay, poking and prodding it ended up being a simple, idiotic mistake. I put the headlight fuse in the wrong spot after visually checking it. left is how the fuses should be arranged, right is what I did! but the fuse had power in that slot.

while reading this sticky and testing the orange wire at the blackout switch then looking at the picture how the fuse box was laid out i realized my mistake!

CUCV Headlight Circuit Explained

The headlight circuit causes many problems for most CUCV users. The GM design could use some improvements as the Headlight Fuse actually provides power for multiple circuits. We will cover those shortly. Let's look at the headlights them self first. Whenever troubleshooting any electrical...

www.steelsoldiers.com

never over look the obvious and start with the absolute basics!