Pulsating lights-alternator problem?
Thread Starter
Racer
Joined: Mar 2003
Posts: 268
Likes: 0
From: Mechanicsville VA
Pulsating lights-alternator problem?
Our '89 has pulsating lights (headlights & instrument panel) when cold, then it goes away. Is this an alternator problem? It seems to be charging OK, at about 14 or so volts when cold, and 13.5 or so when warm. My concern is somehow burning out the instruments...
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Most likely your voltage regulator in the alternator is oscillating when it is cold enough. I doubt any harm will be done to the electrical system, but if you want to live with it and put your mind at ease, look at the waveform across the battery with an oscilloscope when it flickers. A garage with an ignition analyzer can look at the battery waveform. The oscilloscope is calibrated and you will be able to determine the peak voltage while flickering and it shouldn't be above 16.0 volts. While flickering, unplug the alternator and if it stops, the alternator is the cause.
