Driving lights on Deuce go on for a second then go out.

[2003hummer h1]

This is my first M35A2C and Im so proud to own it, drive it and talk to curious people. The service manual is kind of difficult to navigate compared to the H1 S.M. I have a basic understanding of electrical systems but no experience with the Deuce's. Anyone ever run into this problem? "Driving lights come on for a second then go out"
Looks like the wiring harness for the rear runs along the driver side frame, I guess tracing the wires up to the front is a start? Another question is: the accessory switch can not be turned on to check electrical issues? it will load the cylinders with fuel, correct? I have to run the truck to do this?
thanks for any help
Donald

 

[2003hummer h1]

OK, I found that the lights can be operated without turning the accessory switch on. " service manual explains it" I have turn signals, brake lights but the parking lights come on for three seconds then go out and stay out. I wiggled the harness all the way up past the spare tire and no difference. No cut's or scrapes on the harness.

 

[gungearz]

Sounds like it could be a ground issue... I'd check the grounds and make sure the batteries are up to snuff. Then follow the wires to where they go and start checking things till you get back to the batteries. Very simple system to work with... Or you can search the TM's to find where everything goes but that won't help if a wire is cracked or you have a bad connection from being corroded... I don't need the accessory switch on, on mine to get the lights to work. Only to start it. Turning the light switch on by itself should work just fine...

 

[clinto]

What do you mean "driving lights"-the headlights or front parking lights?

Just want to make sure we're on the same page.

 

[2003hummer h1]

Parking lights go out in rear

 

[Ford Mechanic]

Your front parking lights won't be on at the same time your headlights are. Just the way they're designed. But the rear should be, check real good for any short to grounds or corrosion. One real good spot to check is under the hood where the light harness comes out of the firewall and turns down, there is a piece of metel that the harness sometimes rubs. I belive there is a circuit breaker in the 3 lever switch also.

Couple of good realted threads
http://www.steelsoldiers.com/showth...f-on-off-on-off&highlight=light+switch+repair

 

[steelandcanvas]

No, turning the ignition switch on will not load the cylinders with fuel, that is the injector pump's job. You should be looking for a short somewhere, the circuit breaker in the 3 lever switch is protecting the wiring by shutting down the circuit. There is no easy way except to get on the creeper, visually inspect and go over every inch of wiring. Pay paticular attention where the wiring passes over metal chassis components.