Lights Flashing?

[Dabignorski]

On my 1990 cavalier the other night after driving for about an hour or so i noticed that my headlights were flashing alot and so was the dash lights along with that the voltage meter on the dash was going back and forth the whole time i was just wondering if anyone would know what that could mean?

[Macgyver55]

Probably a short in the headlight circuit. It could be in the harness, the dimmer switch or even the headlight switch itself. The system uses a circuit breaker so they will come back on intermittently as to not leave you stranded. When they are dim (shorted) it is putting extra load on the charging system which would explain the fluctuation in the volt meter.

[Dabignorski]

would that also make the heater fan slow down when that meter gauge is fluctuating like that

[Dabignorski]

i also noticed that when i tap the brakes while the headlights are on the headlights would dim

[fishtrap3]

How old is your battery? I have had problems similar and battery was shot..

[Dabignorski]

its only couple months old i also just checked it today with a volt meter and it is saying 12.38 volts so i think that is still good

[Macgyver55]

With the extra symptoms you've added I no longer think that the headlight circuit is the problem. I would start by checking for loose or corroded connections (at the battery and starter) then do an alternator output test. Could be the regulator is going.

[Dabignorski]

well with the symptons bein this do you think i coudl make it another hour on that or not when i started up the car the battery was saying 15 volts so i was thinking that the alternator is also ok

[Macgyver55]

What does the voltage read when the lights are dim?

[Dabignorski]

hmm idk its hard to say i can't hit the brakes and look at the same time with myself

[Macgyver55]

I guess you could unplug the alternator and drive it to see if you still get the dimming and big fluctuations in voltage. If it does that would pretty much rule out a bad alternator.

[Dabignorski]

alright i am going to see if i can make it home tomorrow about an hour and half drive and i will try and doo that and see what happens Thanks!

[Shack]

I would have the battery tested first. The gauge issue shows it is further than a head light/multi-switch issue, unless it is a short to ground. A battery test is free. The braking issue leads me to a battery ( the shift in the car or extra draw of current from the use of brake lights).

Good luck..

[Jeremy airjer W]

 Originally Posted By: Dabignorski

hmm idk its hard to say i can't hit the brakes and look at the same time with myself

Although checking for voltage at the alternator or battery is ideal in a pinch you can hook up your volt meter to a power and ground inside the car. fuses, empty fuse sockets that have a power supply, courtesy light connectors, and 12 volt outlets can be sources. Since your having troubles with lights flickering on the dash I might be inclined to check power at the fuse for the dash lights to see if it fluctuates there.