55 Electricial gremlin

[Fundctr]

I have a 55 T Bird that was converted to 12 volt sometime in the past. Several times lately, while driving down the road my dash lights and clock have suddenly turned off. After a few minutes the power returns and all is fine. I’m guessing there must be some breaker somewhere under the dash that must reset? Has anyone else experienceed this and if so what should I replace? Many thanks in advance for any help.

 

[icarch]

I have a 55 T Bird that was converted to 12 volt sometime in the past. Several times lately, while driving down the road my dash lights and clock have suddenly turned off. After a few minutes the power returns and all is fine. I’m guessing there must be some breaker somewhere under the dash that must reset? Has anyone else experienceed this and if so what should I replace? Many thanks in advance for any help.

I’m a novice compared to the experts on this forum, but I will share what I’ve learned. The only fuse on my 55 that impacts what you described is located in the back of the light switch. The fuse is either good or blown so lights wouldn’t come and go from a bad fuse. When I would lose my lights it was a short in the headlight dimmer switch on the floor board.
I would start by looking at the headlight switch connectors. I believe it’s the control point for the lights and the clock. Keep in mind all I’ve learned is from guys that have owned Tbirds much longer than me.

 

[CSPIDY]

There is a rheostat that is part of the light switch and this varies the light intensity of the dash lights. The contact becomes corroded and this causes your light issues. I pulled my switch, was able to clean up the contact and rheostat. My lights work much better. You can buy new rep pops but have heard they don’t last long. Better to redo the original unless you can find an NOS. Good luck

 

[doug7740]

The problem you are having with the clock and the dash lights is most likely to a defective headlight switch. There is a 20 amp circuit breaker inside the headlight switch that powers the clock and the stop light circuit. Make sure both of these circuits are not causing the circuit breaker inside the headlight switch to cycle on and off before replacing the headlight switch.

The dash lights are powered through a rheostat on the front of the headlight switch. If the dash lights do not work, make sure you rotate the headlight switch while checking. If they do not work or work intermittently, check for continuity between terminal R (black wire) and terminal I (blue wire with red band) of the headlight switch while rotating the rheostat. If no continuity, replace switch.

The fuse on the headlight switch that icarch mentioned in his post only powers the courtesy lamp in the dash and the door jamb switches. If this is blown, check the wiring to the map light and door switches for bare wires especially where the wires exit the kick panels and enter the door jamb.

Hope this information helps.

doug7740
1955 Thunderbird Blue

 

[Dlluinstra]

Bad ground is possible.

 

[Fundctr]

Bad ground is possible.

Thank you all for your input. I will check the switch out this week and report back.