We have a 98 3500 diesel dually that has a bizarre problem with the DRL. They quit working and we discovered the fuse had burned out and when we replaced it, the lights came on even though the truck was turned off and the keys were out of the ignition...they won't shut off until we pull the fuse. The lights work fine otherwise, what are we missing?
Marilyn

 

You should ask this over in the diesel section, or maybe an admin could move it over there for you. They will probably know a lot more about diesels then we do, as we are mostly gassers here.

 

Sorry, I'm presuming it is an electrical problem...

 

Sorry, I was in a rush earlier today, speed-read the part about "diesel" and skipped to conclusions. My bad. Maybe we can help you out after all, then.

Again, my apologies.

Are there any relays associated with the DRLs that might have "blown" as well as the fuse, and are now stuck on?

 

Your Daytime running light module shorted out.
Very common on Canadian vehicles.

 

i'll ask the obvious question where is the DRL module located and what does it look like?

 

It's a 3x3" Black square box.
It's usually under the hood mounted on the Driver side inner fender.
US vehicles usually don't even have the connector to plug it in.