Dome light stays on

[Lefebvre]

I took my dome light cover off to see why the dome light didn't work - and the bulb was not installed - so I put the bulb in and it came on Problem is - it doesn't shut off So here's my question - I have a 1950 Plymouth Business Coupe - 6V positive ground - I unscrewed the dome fixture from the ceiling and the light went off - so I'm thinking that the dome fixture is grounded and that's why the light stays on. I tried reversing the wires - and it still comes on when in contact with the body. How can I keep the body from grounding the fixture? Any help would be appreciated.

Mike

[JIPJOBXX]

Did you check the on oft switch? It could be shorted and you just may have and open circuit. My dome light switch is by the door is yours?

[JIPJOBXX]

Or your switch down by where the door opens may be stuck in the open postion.

[Rodney Bullock]

Ok, I think my thead might help as you have my problem in reverse. I bet if you look at your switch it has two wires and your switch is not breaking the ground. pull your switch and see if you have two wires. I bet if you clean your switch it will do it's job. I used some of that electronic spray.

[greg g]

If you have a door switch look for an inadvertant ground. The switches complete the ground if so equiped. Perhaps over time a wire is goig to a short so the bulb was removed. A short onthe ground side would light the bulb regardless of the switch position. However removing the bulb assures the power does not go past the fixture. If you have only a pillar switch it probably needs to be repalced.

Edited November 24, 2010 by greg g

[Lefebvre]

Did you check the on oft switch? It could be shorted and you just may have and open circuit. My dome light switch is by the door is yours?

I disconnected the on off switch to make sure it wasn't that.

[Lefebvre]

Or your switch down by where the door opens may be stuck in the open postion.

I wish I had a door switch - no such luck.

[Lefebvre]

Ok, I think my thead might help as you have my problem in reverse. I bet if you look at your switch it has two wires and your switch is not breaking the ground. pull your switch and see if you have two wires. I bet if you clean your switch it will do it's job. I used some of that electronic spray.

There is only 1 wire going to the switch - even if I remove the switch - the light stays on.

[suntennis]

The dome lite has power to it all the time. The lite switch has a single wire to it because all the switch does is provide a ground. Did you install the correct bulb? Sounds like a dumb question, but this could be where the problem is. The dome lite uses a special bulb which is a single filament double pole. These bulbs are not found at most parts houses. Double pole means that the end of the bulb has two contact areas, as opposed the the single pole which has only one. Neil Riddle has these bulbs if you need one.

[Lefebvre]

The dome lite has power to it all the time. The lite switch has a single wire to it because all the switch does is provide a ground. Did you install the correct bulb? Sounds like a dumb question, but this could be where the problem is. The dome lite uses a special bulb which is a single filament double pole. These bulbs are not found at most parts houses. Double pole means that the end of the bulb has two contact areas, as opposed the the single pole which has only one. Neil Riddle has these bulbs if you need one.

Good Point - I'll have to check the bulb. Like I said - the bulb was already in the fixture - just not twisted in.

Thanks for all the info everyone.

Mike

[Don Coatney]

Was your front passanger door open when you did this test? The pictured switch just below the hinge will turn the light on when the door is opened without the key turned on.

[suntennis]

Don, One thing I have noticed about your inputs is that many times you support your comments with photos. You do an excellent job by this. Your photos really help. Thanks for your interest and time.

[Lefebvre]

Was your front passanger door open when you did this test? The pictured switch just below the hinge will turn the light on when the door is opened without the key turned on.

I took the headliner off to see where the wires go - there are no door switches - only the switch on the passenger pillar - I looked at the wiring diagram and it looks pretty straight forward and looks like the wiring diagram. I took the bulb out and looked at it - the numbers on the bulb are TOP G-E 1158 21 & 3C 6-8V. I can't tell if there is more than 1 filament or not (even with 2 pairs of glasses - I guess I could get the magnify glass out) If anyone knows if it's just an incorrect bulb - that would be helpful.

Everyone has had some great suggestions - I'll go to an auto parts store and purchase a new switch - just to make sure that's not the problem.

Thanks,

Mike

[oldodge41]

I think it is the wrong bulb. The 1158 is a dual element that grounds through the base. You need a single element that grounds through one of the posts on the bottom......Tim

[Lefebvre]

Thanks Tim - do you know how I can get one of these bulbs - someone said Neil Riddle has them - Is that someone on this board?

Thanks,

Mike

[Rodney Bullock]

If you go to advance auto you can find the bulb you need there. Look at the packages for the bulbs. I think the bulbs are in green and blue packs the green packs are 6volt bulbs and as someone said just look for the 6volt bulb with one dot on the bottom. I did not know they sold 6volt bulbs until one day I was just looking at the different bulbs and discovered it. they say 6volt on them.

[oldodge41]

I think this is the bulb you need if it takes a dual pin base. ( #88 ) You may be able to get them at an auto supply such as NAPA, Advance Auto etc. Look in your socket and see if it has two pins. If it does this bulb should work. It may or may not be the original number bulb as I have no info on your Plymouth. I simply searched out a bulb I think will work....Tim

Edit: On this type bulb the ground is connected to one pin and the hot to the other so the lamp filament is isolated from the socket and the circuit can only be completed by negative to one pin and positive to the other. On the one you have the pins are one for each filament and the case completes the ground circuit thus keeping it lit all the time. Hope that helps.

Edited November 25, 2010 by oldodge41

[Lefebvre]

I think this is the bulb you need if it takes a dual pin base. ( #88 ) You may be able to get them at an auto supply such as NAPA, Advance Auto etc. Look in your socket and see if it has two pins. If it does this bulb should work. It may or may not be the original number bulb as I have no info on your Plymouth. I simply searched out a bulb I think will work....Tim

Edit: On this type bulb the ground is connected to one pin and the hot to the other so the lamp filament is isolated from the socket and the circuit can only be completed by negative to one pin and positive to the other. On the one you have the pins are one for each filament and the case completes the ground circuit thus keeping it lit all the time. Hope that helps.

I have a 1950 Plymouth Business Coupe - yes the bulb has 2 buttons on the bottom. I'll check at the stores you recommended.

Thanks,

Mike

[suntennis]

Neil Riddle as I said before can supply the bulb . His Phone number is 206 - 285 - 6534 and he is located in Washington state. This is a good number to keep since he carries new, NOS and used Plymouth stuff and has lots of knowledge of the cars.

[Rodney Bullock]

I think this is the bulb you need if it takes a dual pin base. ( #88 ) You may be able to get them at an auto supply such as NAPA, Advance Auto etc. Look in your socket and see if it has two pins. If it does this bulb should work. It may or may not be the original number bulb as I have no info on your Plymouth. I simply searched out a bulb I think will work....Tim

Edit: On this type bulb the ground is connected to one pin and the hot to the other so the lamp filament is isolated from the socket and the circuit can only be completed by negative to one pin and positive to the other. On the one you have the pins are one for each filament and the case completes the ground circuit thus keeping it lit all the time. Hope that helps.

I did not know that. I guess technology got better by the 1950's

[Don Coatney]

For bulb information follow this link.

http://www.taillightking.com/