I have an '02 CTD and three days ago the running lights stopped turning off. I can shut the engine down and pull the key and turn the **** until I am blue, but the running light and dash lights stay on. The only way I have found to turn them off is to pull the relay in the engine compartment. If I pull the relay and put it back they do not come back on, but as soon as I turn the **** they do the same thing. Thinking it was a stuck relay, I tried the blower motor relay and the same thing happens.

Any ideas? It seems like it is back feeding, but I thought I would see what the experts here have to say before I start tearing into things. I have not recently done anything to the truck so I don't think it is that.
Thanks for any help or educated guesses.

 

It sure sounds like a current feedback problem. Bad grounds can cause the strangest things to happen. I haven't run into that particular one yet, but I would start by checking for bad grounds on all of the running lights and body grounds. Possibly pull the bulbs for tails, markers, cab markers etc to see if the problem corrects itself( this breaks the current flow to that particular ground). I would think the problem is on the marker circut somewhere, so concentrate on all bulbs for that circut. Also check the ground inside the relay panel box.

 

I'd also pull the headlight switch to make sure it hasn't overheated and melted.

 

Do you mean the day time running lights?...........if you do, then it is most likely a smoked relay on the board in your DRL module.......unplug the DRL module.......if the lights go out when they are stuck on after you unplug the module then that is your problem........

 

Easy way to see that is if your headlights are on but the tailights won't be....

 

I have had a relay stick on. Switch the lamp relay with the horn relay, try the lights and see if they work properly, if not at least you have eliminated that part.

 

I am sorry for the delay in response--I must have not clicked the "Notify me" option.
Anyway, there are no DRLs on my 2002 so I don't think that is it. Also, this will also happen when I only switch the running lights on without turning all the way to the headlights. Once this happens I can rotate the switch to any position and the running lights stay on. It is pretty weird. I have tried switching relays and that does not change anything--once I switch the running lights on they will stay on no matter what--until I unplug the relay. When I reinstall the relay they will not come back on until I turn the switch again.