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70 CUDA.. DOME LIGHT ON ALL THE TIME #2789329
06/26/20 04:35 AM
06/26/20 04:35 AM
Joined: Sep 2010
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Sweden
71redcuda Offline OP
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71redcuda  Offline OP
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Hello all.


The domelight in a 70 Cuda is on all the time,
it does not matter if both doors are closed or open.

What could the problem be??

Any help would be appreciated!

Thanks
Nicklas

Re: 70 CUDA.. DOME LIGHT ON ALL THE TIME [Re: 71redcuda] #2789332
06/26/20 05:03 AM
06/26/20 05:03 AM
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Posts: 5,597
Caracas, Venezuela, SouthAmeri...
NachoRT74 Offline
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A tipical fail for this is the use of wrong bulb. Some ppl uses to look inside the socket and note two contacts and run to buy a 2 contact 2 filament bulbs ( I.E. #1157 ) where the correct bulb is 2 contacts 1 filament ( #1004 )

Reason why using the incorrect bulb will keep light on:
Bulbs like 1157 gets the base used to feed the common ground to filaments, where every contact is just positive for each filament.

1004 bulb gets the base isolated from filament and each contact is used for positive and negative ( ground ) for the only one filament inside.

Since dome light is switched by ground getting constant positive, using a 1157 bulb or similar with dual filament will get one of the contacts constantly feeded by the constant positive source at dome light socket, and will get constant negative ground by the socket, because filaments are not isolated from base. Dome light socket is of course attached to body, so is by default chassis grounded ( hence the reason to use an specific bulb )

The next reason could be some of the door jam switches network damaged ( switch, wires grounding, dome light wheel on cluster damaged )

Re: 70 CUDA.. DOME LIGHT ON ALL THE TIME [Re: NachoRT74] #2789334
06/26/20 05:25 AM
06/26/20 05:25 AM
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Posts: 1,418
Sweden
71redcuda Offline OP
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Yes! You might be right!

I tested a 1157 bulb and it was light on all yhe time..

i realized it should be a smaller 1004 light so hopefully it will work better.

Thanks for the reply!

Re: 70 CUDA.. DOME LIGHT ON ALL THE TIME [Re: 71redcuda] #2789433
06/26/20 12:20 PM
06/26/20 12:20 PM
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Calgary, Alberta Canada
a12rag Offline
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Also don't overlook the dash light dimmer . . . maybe it got bumped and has turned on the dome light ??? Uhh, easiest to check . . .

Re: 70 CUDA.. DOME LIGHT ON ALL THE TIME [Re: a12rag] #2790880
06/30/20 03:06 AM
06/30/20 03:06 AM
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Sweden
71redcuda Offline OP
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Still no luck, i have the correct 1004 lamp installed in the dome light, dimmer switch is rebuilt.. BUT the dome light is still on all the time even the doors are closed..


Any ideas what the problem could be ? The door switches is one thing.. but they are new.. I have only checked driver side and there is a yellow cable and a yellow w blk trace going to the switch..


Not sure how the wire routing is from the lamp and forward..


Any help is appreciated.



Thanks
Nicklas

Re: 70 CUDA.. DOME LIGHT ON ALL THE TIME [Re: 71redcuda] #2790888
06/30/20 06:47 AM
06/30/20 06:47 AM
Joined: Aug 2007
Posts: 5,597
Caracas, Venezuela, SouthAmeri...
NachoRT74 Offline
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driver side should get a 3 pins wire with couple of yellow wires and one black, which handles the lights on and key in warning buzzer signals.

Passenger side should be 2 prongs switch and handles just both yellow wires.

I can make a diagram later, but something is being grounded around on the yellow wire system.

dimmer light on light switch must not get the max point, because that will activate the dome light. Usually they get a small "click" ( not easy to feel ) when dome light is being activated rotating the knob




Re: 70 CUDA.. DOME LIGHT ON ALL THE TIME [Re: NachoRT74] #2790895
06/30/20 07:37 AM
06/30/20 07:37 AM
Joined: Aug 2007
Posts: 5,597
Caracas, Venezuela, SouthAmeri...
NachoRT74 Offline
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this is based on 71 B body diagram but should work the same on E body


Mmmm althought 70s got a diff lights on and key in warning buzzer setup using positive signal to be activated ( and a diode to isolate both warning signals preveinting a "fedback" ) what would explain why you got just 2 yellow wires and not the black one!... but for the dome light ground circuit should be mostly the same

ground door circuits.jpg
Last edited by NachoRT74; 06/30/20 07:39 AM.
Re: 70 CUDA.. DOME LIGHT ON ALL THE TIME [Re: 71redcuda] #2790920
06/30/20 09:22 AM
06/30/20 09:22 AM
Joined: Dec 2004
Posts: 2,179
Wheatfield, NY
Cuda340 Offline
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Originally Posted by 71redcuda
Still no luck, i have the correct 1004 lamp installed in the dome light, dimmer switch is rebuilt.. BUT the dome light is still on all the time even the doors are closed..


Any ideas what the problem could be ? The door switches is one thing.. but they are new.. I have only checked driver side and there is a yellow cable and a yellow w blk trace going to the switch..


Not sure how the wire routing is from the lamp and forward..


Any help is appreciated.



Thanks
Nicklas



Are you sure the new door switches are pushing in all the way to break the ground? I would put a piece of tape or cardboard on the door to make sure the switch plunger is going in for a test.

Re: 70 CUDA.. DOME LIGHT ON ALL THE TIME [Re: Cuda340] #2790955
06/30/20 11:29 AM
06/30/20 11:29 AM
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Posts: 5,597
Caracas, Venezuela, SouthAmeri...
NachoRT74 Offline
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iagree

or pushing the switches by hand

I was thinking on that! when these switches are new I think they "autoset" up by themself once doors are closed. The outer sleeve is inserted/pussed to set when the point contacts inside are closed as soon doors are barelly opened.... OR SOMETHING LIKE THAT. Can't explain it

Last edited by NachoRT74; 06/30/20 11:31 AM.
Re: 70 CUDA.. DOME LIGHT ON ALL THE TIME [Re: NachoRT74] #2790970
06/30/20 12:33 PM
06/30/20 12:33 PM
Joined: Jan 2004
Posts: 1,158
North Carolina
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469runner Offline
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For what it's worth. I purchased new door switches for my '70 'Cuda restoration. Long story short they were crap and I had the originals replated somewhat and they work fine. The replating could only do one color, at least they are clean. I had to do the same with my 1970 Roadrunner. New ones wouldn't work right. Same deal, lights stayed on.

Re: 70 CUDA.. DOME LIGHT ON ALL THE TIME [Re: 469runner] #2790996
06/30/20 01:37 PM
06/30/20 01:37 PM
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central il.
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second 70 Offline
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Door switch might not be working because of paint or bad ground.

Re: 70 CUDA.. DOME LIGHT ON ALL THE TIME [Re: second 70] #2791026
06/30/20 02:49 PM
06/30/20 02:49 PM
Joined: Aug 2007
Posts: 5,597
Caracas, Venezuela, SouthAmeri...
NachoRT74 Offline
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Originally Posted by second 70
Door switch might not be working because of paint or bad ground.


if it was lack of ground dome light wouldn't light on

Re: 70 CUDA.. DOME LIGHT ON ALL THE TIME [Re: NachoRT74] #2791045
06/30/20 03:27 PM
06/30/20 03:27 PM
Joined: Dec 2003
Posts: 3,193
Lansing, MI
70gtx440dana Offline
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Do they cycle on and off when you push the switches in by hand? If so, as suggested they are pushed in too far and do not seat/close properly when door is closed. You should be able to pull the outer sleeve outward to adjust properly.


70 Road Runner 383-4 4 speed FJ5 & black guts
70 Charger R/T 440-4 4 speed FJ5 & white guts
Re: 70 CUDA.. DOME LIGHT ON ALL THE TIME [Re: second 70] #2791104
06/30/20 06:20 PM
06/30/20 06:20 PM
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Sweden
71redcuda Offline OP
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Thanks for all replies. Problem solved,it was a bad doorswitch.

Thanks
Nicklas

Re: 70 CUDA.. DOME LIGHT ON ALL THE TIME [Re: 71redcuda] #2791480
07/01/20 12:28 PM
07/01/20 12:28 PM
Joined: Sep 2003
Posts: 13,011
north of coder
moparx Offline
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glad to hear of a positive solution ! up
beer





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