Tail light/ brake light problem?
 

Got a '36 with 12V negative ground system. Replaced original light switch with modern push/pull switch, problem is only with left rear tail light; with lights on and stepping on brake pedal tail light goes out, with lights off and step on brake pedal brake light works. Any ideas?

Re: Tail light/ brake light problem?
 

Make a good ground for the light sockets.
Bruce

Re: Tail light/ brake light problem?
 

Probably a grounding problem or "sneak circuit" with that left taillight socket. DD

Re: Tail light/ brake light problem?
 

36tudor, did you get the engine straightened out? Please tell those of us that followed that thread what you did to fix it.

https://www.fordbarn.com/forum/showthread.php?t=141256

Re: Tail light/ brake light problem?
 

Couple of things I didn't mention, the brake light circuit is fused and I only show 3.5V at the contacts with bulb removed in the the light bulb socket, but filament is very bright when bulb is in? I ran separate grounds for the sockets but the on on drivers side may be faulty & will check tomorrow.
UPDATE: Right now getting 12+Vs at contacts in light socket, have good second ground but light is dim and with head lights on and step on brake pedal tail light on left side goes completely out, tail light on right is bright and works perfectly. Only one filament on the left tail light comes on.

Re: Tail light/ brake light problem?
 

Update on the engine: Made great improvement with the engine and car is at least drivable now but still runs a little ragged when you increase RPM. The issue was more or less solved by advancing timing but as I say still runs somewhat rough and believe it still is the timing. Have timing light but have been unable to get a clear view with light at pointer and mark on pulley. Am going to try and put a piece of tape on pulley to see if that helps. Drove the the car today OAT was 92° and temp went up to 220° and wonder if this is a result of bad timing. Will report back tomorrow. BTW, there was nothing wrong with disturb. Bubba's set up for me; am now just having a problem getting it dialed in.

Re: Tail light/ brake light problem?
 

Problem solved, it was a bad ground as suggested earlier, established new grounding source and everything works as it should.