Weak Blinkers Body Ground etc

[Dan O]

Hey guys - I am working on a 1949 Roadamaster 76S. The blinkers work at different rates in the back - one is slower than the other. My mechanic thinks there is a lack of a ground from the battery to the frame. The battery is currently grounded to the motormount which is how it's always been. Is there some other grounding method we are overlooking? Does anyone have an explanation for the slow/varied blinking? I think it is poor rounding at the housing.

Also, I am getting a new brake light switch but the old one seems OK but there is a lack of power to it. Is there a fuse? I suspect bad switch or broken wire.

Happy Motoring!

[Jim Cannon]

your mechanic is half right. the bad ground is at the light socket(s), not at the battery. a common problem with old cars.

[Guest simplyconnected]

Grounding is essential; make sure all your bulb holders are properly grounded. Your blinker unit works by 'measuring' current through a bi-metal strip (resistor). If you have bulbs of different numbers (different resistance), the left will blink at a different rate from the right. Adding (plugging in a trailer) or subtracting (blown) bulbs causes different blink rates too.

I made it a practice to run a continuous unbroken copper ground wire (#8) from the front of my car to the rear, clamping it in several places along the way. This sounds extreme, but really it is not. Things like your fuel sender (in your tank), depend heavily on a good solid ground. You can see light bulbs work; other things you can never see.

Modern cars run BOTH wires to all bulb sockets.

[Guest Two Roadmasters]

I made a separate wiring from every light bulb unit to a grounding wire that I had built into both the front and rear harnesses. From a joint under the dash, both grounded wires could be connected to a third wire going directly to the battery. This has worked out great on my -38 for the last 15 years with no problems whatsoever.

Mats

[Guest simplyconnected]

Just as an afterthought, you know those bulb holders with the parts that fall out (spring, pigtail, etc). You can easily solder a wire onto the outside of the steel shell with enough heat. Just make sure you empty everything out first, then gingerly heat the shell with a propane torch. As soon as your solder starts melting, pull the heat off. Good electrical solder (40/60 rosin core) will work just fine, and you will have a great ground on each socket you do. Put some silicone GREASE inside socket to keep the moisture out and stop any corrosion.