signal light problem

[STEVE CLC #16187]

On my 1949 Cadillac 62 series I  re wired the front headlights, signal lights and park lights. everything works great except the indicator arrows on the dash. They both flash when every either the left or right signal light is on. I converted to 12 volt and have changed all the bulbs. It acts like a poor ground . I never wired anything under the dash just changed bulbs. I did install LED bulbs in the tail,stop and signal lights,  in the rear only.

steven hales

[Doug Houston]

Was there a reason you needed to change the electrical system??  It'd better be a good one!!!

[cadillacmike68]

Was there a reason you needed to change the electrical system??  It'd better be a good one!!!

He wanted to and it's his car. That's reason enough.


Wish I could help with the wiring, Steve, but 40s are not my specialty.

[Roger Zimmermann]

Maybe this comes from the flasher (sorry, I don't remember the correct name, I'm not at home); the current may not be in the correct range for it.

[J. Gomez]

Steve,

Since you have changed the front, pilot and rear bulbs to LED type, the setup is skewed.

The way Cadillac made the turn signal setup for the dash board pilot lights with the three prong flasher is;

When the turn signal switch is on the RH side position the RH side pilot light will pick up the ground from the LH front signal light filament to chassis ground.  The reversed occurs when the turn signal switch is turned to the LH side. Both pilot lights are tied together at the "P" terminal of the flasher.

Since the LEDs do not have a simple resistance as filaments bulbs do, the dash pilot lights are tied together at the flasher both will blink. The same condition will occur if the bulbs either pilot or front ones are changed with different resistance values. This explanation is at a high level.

You could try changing the front bulbs to regular filament type and see if that change; although I would guess it will not. You may need to go with the old filament type for the front and pilot lights.

Hope this helps..!

Good luck

[gary griffin]

   Often when you change things you get something different than you expected. One would have to look at all parts of the system to figure out what happened here.

    When I started restoring my 1942  6719   I considered changing the electrical system also but opted to restore the old system instead with special attention to the whole grounding system. I figured something would go wrong if I figured I was smarter than the Cadillac engineers were but I also know that many older cars get converted to 12 volt.  I was 22 before I got a 12 volt car.

    For my restoration I will buy the best and strongest six volt battery I can find and keep it on a float charger and that should be sufficient. Probably an Optima but I am not sure yet.

    Good luck with your system Steve.

[STEVE CLC #16187]

Thank you guys for all your input, especially you Mr Gomez, that was a very detailed and technical explanation. I suspected the LED rear lights. I tried them in my 1946 Chevy, another 12 volt system, and the tail lights would come on with the ignition turned on. The reason I changed to 12 volt was I repowered the Cadillac and the new engine was a 12 volt. I have 6 volt cars and don't mind the 6 volt system I get a long fine with it.