Courtesy lights will not turn off

Tiny
FERNANDO228
  • MEMBER
  • 1992 CHEVROLET SILVERADO
  • 5.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 150,000 MILES
I have a 1992 1500 series 4x4 v8 Chev Silverado with approx. 150000 miles on it.
The problem is, just recently the interior(dome& two floor) lights came on by themselves while I was driving. Since then, they wont shut off. The only way I can shut them off is by removing the courtsey fuse from the fuse box.
I've replaced the two door jam switches but, still have the same problem.
The interior lights will flicker from time to time and sometimes shut off briefly while driving but, stay on for the most part. My aftermarket radio/cd player runs off the same fuse as the lights but works fine even though the lights flicker or shut off briefly. I've had the radio/cd player in the truck for 5 years so, I don't think that's the problem.
The interior light dimmer switch seems to be working correctly. It allows me to either turn off the dash lights completely or put them to their brightest.
All other electrical works fine and I haven't had any electrical problems up until this time.
Any tips on how to possibly solve this problem would be appreciated.
Thanks
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Saturday, October 3rd, 2015 AT 8:12 PM

6 Replies

Tiny
CARADIODOC
  • EXPERT
Solving this could get a little messy, but we can start with some easy stuff. Your observation about the radio being on the same circuit is valid, but that is the 12 volt supply for both circuits and it feeds the interior lights all the time. The lights are switched on the ground side of the circuit. That way only one wire has to run to each switch, and the other switches' wires are just tabs that are part of their mounting hardware. The exception is when the switch is mounted to a plastic part such as when GM puts them on the side of the dash pad, or when there's multiple circuits being switch by that switch.

The first thing to do is remove and unplug every door switch. There may be one on the side of the dash and another one on the "B" pillar near the door latch's striker. You'll also have to unplug the head light switch. The rheostat for the dash lights and the dome light switch are two totally different parts of the switch. Also, if there is anything that causes a delay in turning off the lights, you'll have to find that too and unplug it.

At this point, if you measure the voltage on any wire that was connected to a door switch, you SHOULD find 12 volts and the lights should be off. If the lights are still on, you're going to find 0 volts indicating that circuit has a short to ground somewhere. This is where it can get messy by taking a lot of interior panels apart to find the short. Before we get to that point, since the intermittent flickering tells us this isn't a solid grounded connection, consider running around the truck with a rubber hammer. Watch for flickering as you pound in various places.
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Saturday, October 3rd, 2015 AT 8:54 PM
Tiny
FERNANDO228
  • MEMBER
Thanks for the info did all that and still lights won't come off any other suggestions
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Sunday, October 4th, 2015 AT 7:33 AM
Tiny
CARADIODOC
  • EXPERT
Next, remove the dome light assemblies. Some designs have socket terminals that can touch the body if they aren't positioned correctly, particularly those that use the tube light bulbs that have a round cap on each end. These assemblies often get their ground circuit through the mounting screws.

This is where it gets messy. An orange wire feeds the 12 volts to most of the lights. They have white wires that get grounded by any of the switches to turn all of them on. Those white wires run to every light socket and to every switch. If any of those wires has rubbed through the insulation and is touching the body, all the lights on that circuit will turn on. If you can't find a clue as to the location of the short by wiggling and tugging on the wires, you have to start cutting them apart. Later you'll have to splice all those cuts back together.

Think of having a leak in an underground lawn sprinkler system. There's no way to tell where the leak is. All you know is water is flowing through the main pipe. To isolate the branch with the leak you would have to block each circuit until the leak stopped. That means turning off various valves to the individual branches. Cutting a wire is like closing a valve. The only problem is soldering and sealing all those cuts takes a lot more time then turning a valve.
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Tuesday, October 6th, 2015 AT 12:36 AM
Tiny
FERNANDO228
  • MEMBER
Th Thanks will try again I did notice that on the dome light there is a white wire that touches the truck body I should disconnect. And see if all the lights turn off
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Tuesday, October 6th, 2015 AT 5:53 AM
Tiny
CARADIODOC
  • EXPERT
Yup. The white wires go to ground through the switches, not directly.
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Tuesday, October 6th, 2015 AT 6:15 PM
Tiny
FERNANDO228
  • MEMBER
Nothing seems to work I give up
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Friday, October 16th, 2015 AT 9:06 PM

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