dome light gremlins

[Super77]

Anyone had this problem?

My main dome light cuts out sporadically. Won't work in any position. Wiring continuity looks good from the ceiling to the fuse, and at moments when it's out, I still measure 12V at the ceiling terminal, so I'm suspecting the housing or the terminal pins. A close look at the former reveals no cracks or corrosion. I recently applied a dab of dielectric grease to the pins and the little ball bearing on the switch. We'll see if that makes a difference.

I did replace the stock lamp with a 4-pot festoon LED, but swapping it with the rear dome LED (which works fine) gave the same results. So, perhaps the lamp is not to blame.

 

[88bj73]

I too have this problem... Happened once i put the LED in. Hoping someone chimes in as it's been bugging me for ages and can't seem to figure it out.

 

[Desert Tortoise]

Check the ground return. Factory manual wiring diagram shows that the dome light switch connects the lamp to ground. Likewise the door courtesy light switches provide ground in the other on position. So maybe pull the lamp and see if there is continuity from one lamp connector to to ground. Mine seems to do the same thing intermittently but I have successfully ignored it for years.

 

[Crick60]

Voltage doesn't always mean power, if you have a shunt setting or attachment for your meter try using it to measure the voltage.
It really sounds like a bad ground and the inherent impedance from the meter may cloak that if the negative return is corroded or loose or high resistance.
I'd be suspect of the door switch, you can rule that out by grounding straight to the screw in the light fitting and using the on off setting and not door.

 

[MACFJ60]

I have the exact symptoms. Dome light 4 LED festoon bulb works in the on position, but won't turn on in the door open position. In addition, When I replaced the cargo area to LED, it would not turn off completely. I have compromised by running a conventional bulb in the cargo area and leaving the LED in the center dome light. Would be nice to have bright LED light fill the cab when a door is opened.

 

[Crick60]

Take the switch apart at the door and ground both wires to the battery negative or a good body bolt.
If the LED comes on and off clearly you have a ground/negative return problem, typically it's the connection past the switch to the body (I've not played with that wiring so I don't know where it is but it should just be a wire from a body bolt to the switch then off to the lamp.
It could also be the switch itself and you can test that by tapping the wire from the body to the wire to the lamp at the switch and watching for your symptoms or lack there of.

I'll try and pull mine apart tomorrow and see if I can post something up.

Another thing you should try is measure the voltage or lack there of between the battery negative terminal and the lamp negative wire or terminal, there should be 0v when the door is open or in the on position (lamp out).

 

[sved]

Led's draw a lot less amp's then normal lamps.So they will not have the normal ''contact cleaning effect '' caused by small sparks like normal bulbs.That could be your problem.Door and hatch contacts?

 

[Super77]

Take the switch apart at the door and ground both wires to the battery negative or a good body bolt.
If the LED comes on and off clearly you have a ground/negative return problem, typically it's the connection past the switch to the body (I've not played with that wiring so I don't know where it is but it should just be a wire from a body bolt to the switch then off to the lamp.
It could also be the switch itself and you can test that by tapping the wire from the body to the wire to the lamp at the switch and watching for your symptoms or lack there of.

I'll try and pull mine apart tomorrow and see if I can post something up.

Another thing you should try is measure the voltage or lack there of between the battery negative terminal and the lamp negative wire or terminal, there should be 0v when the door is open or in the on position (lamp out).

^ this.

However, I should add that I have gotten the light to turn on half the time with a firm smack to the roof near the fixture. Could be coincidence, but I have been assuming the problem is somewhere in the ceiling.

 

[Output Shaft]

My dome light when bye bye a few years ago. Would blow the fuse if I flipped the switch. Just happened one day. Could never fix/find the problem. I suspect mice nibbling or insulation chafing from the vibration of all the rough dirt roads.

My Solution:
Wear a strap on headlamp. Lighting is WAY better in every respect.

 

[hj 60]

It was this in mine, the dontknowenglishname broke off and replaced with bolt&nut:

 

[John McVicker]

Hj 60, good post & good work around.

John