Dome and trunk light won't turn off...

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RJK3

RJK3

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73 Duster. The dome, under dash and trunk light are all on ALL the time. I've tried to find the short but had no luck. Anyone else seen this that could point me in the right direction? The blinkers don't blink like they should as well.
 
For the dome light, chk the switches in the door frame to make sure they are breaking the contact when the doors are closed.
You'll have to pull the kick panels to chk the wires also, because the dome light works by grounding the circuit so if one of the wires came off the back of the switch and fell down making a contact to the body it will make the lights stay on all the time.
The trunk light should only be on when you open the trunk, so chk the switch there also.
That might just be an adjustment of the switch position.

The signals you might want to take on as a seperate issue in a separate post.
 
EDIT I see were were both typin' and postin' at the same time, LOL


1---trunk............This is a simple circuit. The lamp is not grounded, and has a wire which you can easily trace, going to the trunk lid switch. The switch grounds when you open the trunk. Try unhooking the wire. If not, it's a bulb or socket problem

2---Dome--------You have a map light switch? If so, this complicates things. If not, there are three things that turn the dome on. The two door switches, and the headlight switch. Make sure the headlight switch dash dimmer control is turned somewhat to the right. If this doesn't do it, disconnect the door switches, and last, disconnect the headlight switch. Dome ground leg switching is done on the yellow wires. If none of this works, it's a bulb or socket problem, or a crossed wire somewhere in the harness.

3----Signals. "don't blink like they should" is not a description. Need more details. Fronts don't work? Rear? Blink slow? what? What exactly is the situation?
 
Thanks for the reply. I've checked all of the switches and the wires leading to them, all seems to be fine... I thought the signal issue may be tied to the ground issue I'm having with the other lights. The blinkers will blink once or twice then just stay on. I've not replaced the blinker switch yet, just not sure I need to yet.
 
If you can, get an electronic flasher as they don't rely on an electrical load to flash and it makes it a lot easier to change or work with the signal lights.

When it does flash, do they seem to be normal on the outside of the car? (Do they light up normally but not flash?)
 
In most models the wires for dome lamp, trunk lamp, etc.. have a tape out connector from the rear harness in trunk above left wheel well. If the problem isn't there, look at the connection behind left front kick panel. If the problem isn't in/at one of these connectors, the wires run under the carpet along the left door opening.
If you have a Space Duster, folding rear seat, or some other feature that I'm not familiar with, another owner may chime in with clues. Good luck
 
Would a problem with the dimmer switch on the dash have anything to do with this issue?
 
It is a Space Duster. There is a "map light" switch. I have swapped the headlight/dimmer switch, no change.
The blinkers are bright on the outside of the car. They flash a time or two, then stay on.
 
RJK3 said:
It is a Space Duster. I have swapped the headlight/dimmer switch, no change.
The blinkers are bright on the outside of the car.
Click to expand...

If the trunk light stay on it's not the wiring from the front causing it.
It's a fact that it's getting a ground when it shouldn't and that ground is in the trunk.

For the interior lights you can do a quick easy chk by unplugging the door switches and making sure they are isolated from ground, and that the headlight switch is in a position as to not cause them to be on.

If the lights are still on, then you need to find where they are getting grounded.

I would start the blinker diag with a new blinker canister and go from there.
It sounds like they work, but just don't flash.
 
I'll pick up a flasher/canister this weekend and give it a try. Thanks for the suggestions.
 
burdar said:
Would a problem with the dimmer switch on the dash have anything to do with this issue?
Click to expand...

At one end of the dimmer rotation the dome lamp is turned on so yes that may be part of the problem. Can we assume you know where the switch for the trunk lamp is ? Do you electric trunk/hatch release ?
They aren't all the same.
 
Well, I replaced the flasher. The blinkers work as they should now. The dome light issue is still there.
Checking with a test light/multimeter, should I be seeing voltage to the ground circuitry? I'm getting voltage in the yellow wires, which I thought were ground.
 
Yellow is the ground leg. switching lead, so with the courtesy / dome lights off, the yellow will be hot. With a door open, or the dash dimmer actuated for dome lights, yellow will be grounded.
 
Hmm...this is making me feel dumb...
With the dimmer to full right, the door and trunk switches disconnected, the map light switch disconnected, lights are on and I have power to the yellow. Just to throw another wrench in the mix, the light in the glove box works as it should...
 
The trunk light has a seperate Ground through the switch mounted on the rain gutter that shorts to ground when the trunk opens. It gets power from the pink dome lamp wire.

Isolate it by disconnecting the body to dash harness at the kick panel on the drivers side. Check the yellow to ground on the body side of the harness with the door switch unhooked or the door closed.

There is a short pink/yellow harness at the trunk were the trunk lamp is patched in to dome lamp harness. The black wire that comes off that harness feeds power to the trunk lamp.

With the body to dash harness disconnected no power should be on the pink so the yellow should not have power either.

If the map light goes out after disconnecting the body harness as well you have a ground on the yellow somewhere under the carpet or up to the dome lamp.
 
RJK3 said:
Hmm...this is making me feel dumb...
With the dimmer to full right, the door and trunk switches disconnected, the map light switch disconnected, lights are on and I have power to the yellow. Just to throw another wrench in the mix, the light in the glove box works as it should...
Click to expand...

Have you checked light bulbs? Not only for proper part no and socket type, but that they are OK?

EXAMPLE. The dual contact dome light bulb internally shorts to the shell. This would be rare. If the short is on the power side, it will blow the fuse. If it's on the yellow wire (switch side) the bulb will light regardless of what the yellow does.

In the above case, opening a door should blow a fuse


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Try to isolate the problem........what happens if you disconnect the map switch? Pull the bulbs one at a time?

Pull ALL the bulbs and see if the yellow is still hot
 
At this point I feel like I've tried every possible scenario, I think I need to put everything back together and start over. If I remove the time delay relay, the voltage seen in the yellow wires goes away...but the lights are still on.

The bulbs are new, the sockets are OE.
 
Does this car have a light at the ignition switch ? If it does or did, I think you'll find a yellow wire in the steering column too. If its shorted to ground there would be lights always on.
 
67dart273 has a good point about the bulbs.

The trunk lamp has a seperate ground switch from the doors and should only light when the trunk plunge switch makes to ground.

I would start there and confirm you have a 1004 bulb installed. Then move on to next and confirm it has the right bulb.
 
Any updates RJK3?

Hope you have made progress!
 
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