kent

I have recently bought a 2000 Chevy tracker, the headlights and the interior lights pulsate while driving down the highway. This happens sometimes, then for no reason quits, then starts up again. They normally stop pulsating at lower speeds or when it is idling. I have replaced the alternator, the battery. I have also checked every fuse. I have wiggled every wire i can reach, to see if I can find a short with no luck. Every ground wire seems to have a good connection. I have taken to a local garage and the mechanic was no help, but said everything tested good. Does anyone have any ideas I can try next. thanks Kent

maxxman04

in my experience, the pulsating usually means that the alternator is going out. try this for a home test. get yourself a voltmeter, start by hooking leads to your battery, start car, note the voltage reading. then start turning everything on, checking the voltage as you go. at idle, with everything on,(headlights, a/c or heater, interior lights etc) you shouldn't really have a drop in voltage. normal is 13.5 volts, maybe a bit over 14. if voltage drops below 13 at idle, have alternator double checked and battery.

thepitchpatch

I had the same problem with my 2003 Tracker - a new alternator fixed my problem. Perhaps you bought a rebuilt or used "new" alternator? The one I bought was new, as I've read that many of the rebuilds are not any good. The new one I bought cost under a hundred bucks, which was less than the rebuilt ones I found.