Pulsating Electrical System

My 2002 Tracker’s electrical system pulsates. This started before replacing my battery and has continued since replacement. Pulsatin happens in lights, fan, and even engine. Pulsation rate (2-3 pulses/second)does not vary with RPM change. Any ideas?


have the alternator tested.

Does it pulse even if the engine is not running?
Turn the key to ACC, does it still pulse?
Turn the key to RUN but not START, after 10 seconds, does it pulse then?
Or only when the engine is running?

The pulsing only happens while the engine is running. It beging about five seconds after starting engine.

I have to think that this trouble is coming from the alternator some how. There is an easy way to prove it. Before you start the engine remove the connection on the back side of the alternator. This will disable it so you can see if the alternator is causing the trouble. Start the engine and see if the pulsing doesn’t happen then.


Sounds like the consensus is alternator. I’ll have it tested. Thanks.