cLAYH

My dad now has my 2001 3500. He is in Moses Lake, Washington with it and his 5th wheel. His dash lights and taillights/marker lights have stopped working. He has checked the park lamp fuse and its shows 12V on both sides of the fuse. He has also replaced the dash head lamp switch. No improvement.

Is there a relay somewhere for this? Any other thoughts/suggestions? He is an instrument tech and has a few basic hand tools and a mulitmeter at his disposal.

Thanks.

cLAYH

If anyone has a wiring diagram of the park lamp system they could send me I would appreciate.

Also he hasn't hooked up to the 5th wheel in over 3 months,its parked there while he is working. This just started a few days ago and wasn't caused by the trailer.

Busboy

It could be a burnt wire at the headlamp sw. If there is ANY discoloration then that is the problem.

tlcavvy

i had to put a blinker switch in mine when it did that exact same thing... was like $140... awesomeness.

cLAYH

Blinker switch? You mean for the Hazzard lights? I wouldn't think the park lights would run thru that switch.....

AndrewK

You should have two fuses for running lights, one in the truck and one under the hood. The one under the hood is effected by a trailer. 9 times out of 10 thats the one the has blown for me.

cLAYH

Ok he found the fuse under the hood for the marker lights and it is blown. Putting in a new one just blew right away. There is no trailer hooked up. Any more thoughts?

GAmes

Has he looked at the 7 pin receptacle for corrosion, or under the truck for a chaffing wire?

cLAYH

He disconnected the the 7 wire plug at the back of the receptor, no change. Has yet to crawl under for a good look.

cLAYH

I there an easy place to disconnect the wiring harness for the rear lights at the front of the truck to isolate where on the truck the problem maybe? What about at the back?

Lil Dog

There should be a plug near the spare tire to branch out to the rear of the truck for lights and trailer. I would pull that off and see if it goes away, then pull out a DVM and check for shorts in the harness.

Bluedually4x4

Stupid question, but does the truck have the factory radio in it, or is it aftermarket. I had that same problem and it was caused by the radio's wiring harness. The wire that tells the radio to dim when you turn the lights on was shorted out and that kept blowing the fuse.
I hate the wiring in these stupid trucks.

GAmes

Did he try disconnecting the brake controller?

cLAYH

Yes it does have an aftermarket radio but its a good quality Kenwood and its been in a LONG time. Just in case though were you blowing the underhood fuse or the dash fuse?

cLAYH

Nope. How does the brake controller affect the parking lights? Brake lights I could see but there are only 4 wires on the brake controller, power, ground, brake line tap and then out to the trailer plug. Am I missing something?