Hello Cadillac family I need some help. I am having an electrical issue and trying to pinpoint what may be causing my issue. With the car running and the headlights on for a bit all of the lights start acting funny. All of the lights will turn off and on and I’m not sure where to start looking. It seems to start doing this after the lights are on for 10-15mins or longer. When the car is cool it doesn’t seem to have the issue.  Any suggestions on what to test?

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could the headlight switch be causing this issue? can i take it apart and clean the insides? anything i should look for when i take it apart?


looks to me like you need to be cleaning all the ground connections related to the headlight circuit  and possibly the charging circuit ( regulator grounds ) 

Include the most important ground —under the battery tray to the frame from the negative battery terminal 

Clean connections to shinny metal and reinstall 

The up side is that most times all electrical comes back to life just doing that on these old cars that develop intermittent connections from age and exposure to the elements 

A Dremel with a cutting disc is a good tool to clean  up grounds 

A cheep —just time consuming freshening up of the electrical system

Cleaning  the grounds is the very first thing to do with any electrical issues with our year Cadillacs and then go from there 

The electrical connector plugs can be disassembled to clean the individual terminals inside them  if needed

You have a little spike holding the  individual terminals in the connector that needs to be suppressed so the individual wires can be removed from the connector and cleaned 

That should help 




Poor connections cause high resistance, and that is causing the circuit breaker to trip in the headlight switch.

Check the dimmer switch connector, as that gets wet often. 

I do have a headlight relay wire harness that does fix the issue.  Your headlights and dash lights will be brighter, and it is a simple installation. No cutting of wires, just plug it into the existing headlight connector. 

70.00  plus shipping, just email me at russ85747@hotmail.com  

Russ, I have heard nothing but good things about your harnesses and they are a good fix to take the load off the switch, especially if someone is using a high amperage draw bulb like a Halogen ... but I must point out the statement about higher resistance isn't exactly correct.

When resistance goes up the amperage goes down with a constant voltage (12 volts).

Ohms Law tells us V (volts) = I (amps) x R (resistance), so solving for I, the formula is I=V/R and with the voltage a constant (12 volts) the amps (I) goes down as the resistance in Ohms (R) goes up.   

Easiest way to think of this is the old hose pipe analogy. If your water pressure (Voltage) is say 60psi, and you have nozzle wide open (low resistance), you will get the max amount of water volume. Now start to close the valve (increase resistance) and the water volume goes down.

Circuit breakers, like fuses, react when an amperage is reached but unlike a fuse that blows, a circuit breaker will reset.    If the circuit breaker is triggering (resetting off and on), then something is probably shorting or leaking current across the switch or again if these are high amperage draw aftermarket lights then that is the problem and your relays are an excellent solution.

Also as noted prior, it is important to check the grounds. If  headlights are original or have not been changed then I would take a close look at those forward lamp harness grounds just in front of the radiator support and all other grounds.  You can see the Forward Lamp Harness grounds and other grounds on our Ground Strap Locations help page. 



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