Needing help with pulsating lights. First off I have a 1970 oldsmobile cutlass
that I purchased 7 months ago, I have done a lot of work to it and now ran into a problem that I can not fix. My headlights seem to pulsate or dim and
brighten when the engine is on, I have changed the alternaor and still the
lights seem to pulsate. When you give it gas it seems to stop but only for 2-3 seconds and then continues to surge or pulsate. Thanks in advance for any help you can provide. Oh by the way does anyone have a wiring diagram they
can scan and shot my way, would surly appreciate it, thank markm.

 

Try checking and cleaning all connections in the headlight circuit, they could be corroded causing unnecessary resistance. Also you could consider adding relays to make the circuit shorter thus having less connections and less resistance. Here's some info http://www.madelectrical.com/electri...adlights.shtml

 

Check and clean all ground connections including the voltage regulator mounting screws, and the engine-to-chassis ground straps.

Sometimes a weak headlight switch will cause this. The switch has a circuit breaker inside it.

Bite the bullet and buy yourself an original 1970 factory Chassis Service Manual. It will have clear color wiring diagrams that generally lose a lot in a scan, in addition to other invaluable service information.

 

Just to echo what these guys said, that was happening with my old Dodge pick up. I found that the hot wire going to the amp meter in the dash was very corroded. Cleaned it and put a new end on it and no more problem. (other than it still being a Dodge)

 

Are you sure your belts are good & tight ? Does the alt run off the crank or water pump if its the pump the Ps belt is slipping

 

Hey guy thanks a bunch your quick answers help alot, all I did was check all my ground and found the horn relay was not grounded good enough. With a little bit of cleaning fixed the problem, no money required.. I will be posting a pic. of my project car make sure to check it out..
Thanks Mark.....