Truck head lamps (not DRL) turning on by themselves and staying on

lights
chevrolet
2500

#1

I have a 2003 chevy 2500HD with 125K miles on it. For the last couple of months, the lights have been coming on at all times of the day. So I thought relay issue and replaced the relays.



The problem never went away. So took it to the mechanic for a check. He said burnt switch and replaced it. Only $250 out of the pocket.



The problem is that this is still happening after switch and relay replacement.



If I find the lights on, only way to turn them off is to drive the truck around the block. The lights go off for next 24-48 hours. On longer than 24 hour parking, I am having to pull the relay for headlamps to save battery.



Any help?


#2

An easier way to disable the lights may be to locate the fuse that ties to them and pull it out rather than the relays. At least until the trouble is found.

Since replacing the switch didn’t fix the trouble it sounds like the problem may be within the wiring after the switch. You sound like you are the type that can do your own work, at least to some point, so I recommend you purchase the factory wiring manual for the truck. It will show you how things are tied together and where to locate them. You have already spent a good amount of money on the trouble needlessly. Replacing the switch was a good guess but it wasn’t proven to be the trouble and you got stuck with the tab.

I don’t know how the relays are switched on but they may use a ground connection from the switch to turn them on. If the relay control wire is making an intermittent ground sowewhere that would cause the trouble. Having the service manual will guide you on what to look for. It is an investment that you will be glad you made.

One thing you might try to help you locate the problem area is to move suspected wire harness points around with your hand to see if you can get the lights to turn off when the trouble occurs. If the light switch is located in the steering column that would be a highly suspected area for the trouble in my book.


#3

I believe they are controlled by a relay and relays sometimes stick. If you can find the relay you sometimes can get them working for a while with a reasonable whack with the big end of a screwdriver.


#4

Are the lights wired through a “Multi-function stalk switch” mounted in the steering column?? These can be trouble prone, especially the dimmer switch function. Too many wires in to small a space…