need help on electrical problem
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 3,268
Likes: 2
From: Minnesota in the summer, Las Vegas in the winter
need help on electrical problem
Yesterday my '91 began doing strange things. The dash lights started intermittently flickering. The voltmeter goes from about 9 volts at idle to about 16 or 17 at highway speeds. When I use an electrical device such as a window switch, the tachometer needle jumps up and down as that device is used and not used. The battery does not seem to be fully charged, but will still start the car. I can see a small fluctuation in the voltmeter needle when anything is turned on or off. The flickering of the dash does not go away, whether idling or driving at highway speeds. This is a stock L98 with 93000 miles.
Help is appreciated. Thanks
Dan
Help is appreciated. Thanks
Dan
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: need help on electrical problem (brdd)
With the engine running, unplug the connector on the alternator and observe if the dash flickers. If it stops, the voltage regulator in the alternator is oscillating and you need a new regulator or replace the alternator. Recharge your battery from a 120v battery charger, don't expect the new alternator to do it!
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 3,268
Likes: 2
From: Minnesota in the summer, Las Vegas in the winter
Re: need help on electrical problem (jfb)
With the engine running, unplug the connector on the alternator and observe if the dash flickers. If it stops, the voltage regulator in the alternator is oscillating and you need a new regulator or replace the alternator. Recharge your battery from a 120v battery charger, don't expect the new alternator to do it!
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Re: need help on electrical problem (brdd)
Yes you should be able to replace the voltage regulator and while you are in the alternator you may as well replace the brushes as well. These parts are available from your local NAPA store. Just give them the current rating and also the service number that is stamped on the alternator case. In some cases where the alternator was replaced by a remanufactured unit these numbers may not exist. But the counterman should be able to figure it out by application.
As for the tach problem, check all of the engine and chassis ground connections. There maybe a loose ground somewhere.
[Modified by tjwong, 10:34 AM 9/14/2003]
As for the tach problem, check all of the engine and chassis ground connections. There maybe a loose ground somewhere.
[Modified by tjwong, 10:34 AM 9/14/2003]
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: need help on electrical problem (brdd)
A discharged battery can cause light flicker when using the window switch, but the tach shouldn't be affected I wouldn't think. Another thing I would do is to remove the battery cables (neg first) clean the cable lugs and the battery posts and replace (neg last). Poor battery connections can cause voltage fluctuations with current fluctuations. Charge the battery up too!
