my headlights or dimmer headlights won't turn off when key is removed
Headlight relay~ https://www.google.com/#q=2002+Chevrolet+Express+G1500+Passenger+ Van+headlight+relay&tbm=shop
....else the GROUND is clobbered up with corrosion...you might take the black 1/0 cable from where it attaches to the ground.....wirebrush the lug...wirebrush the chassis for FULL grounding potential to all devices....including the ECU~
Judge Roy is right on again. My question to you, did you use the correct replacement? If you have a timer delay, it may take a different switch. Always clean the connections before putting in new replacement parts, especially electrical. The older ones develop electrical corrosion around the connectors over time and a lot of times, cleaning of the existing parts is all that is needed to do fix and/or repairs. 000 emery paper and a good electrical cleaner such as as-atone spray will work clean the connections.
I've had the same problem and I've fixed it. In my case it was the daytime running headlights module that went bad and got so hot that it started to melt. I just removed it and now no problems, the headlights still turn on when I turn them on with the switch. It's located under the steering wheel on the right side close to the engine cover. It gets hot when the battery is connected so an easy way to find it is, drive around for a bit, then stop, get on the floor under the steering wheel where the pedals are and on the right side look for a black plastic box (about 2" x 3") and see if it's hot, if it's hot then that's your problem. If it's not hot, disconnect it anyway and see if it fixes the problem.
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