C4TOMCAT

Hope you can help me with this problem. My cousin has an 86 corvette automatic and recently he has been experiencing his interior light flickering. They do not flicker until the car is started, then the instrument panel lights flicker about 5 seconds after the car starts. Also the interior dome lights flicker at the same rate as the dash. Is there a common source that feeds these circuits. He has disconnected the alternator connections, cleaned all the grounds, except the one he has been told is behind the IP but he has not found it. The 87 manual he looked in shows it but he is unable to find it on the 86. There is also one that is supposed to be to the left of the steering column but can not find that either. Is it under the insulation? He has put new distributor cap, plugs, wires and still it flickers. He has cleaned the back terminals of the instrument cluster thinking it was the dash contacts. He is also picking up a popping noise in the Bose system.....are these interrelated or just co incident. Any help will be greatly appreciated

NHVett

I got this when I had a bad voltage regulator in my alternator. The same alt had a diode that was loose and arcing. One indicator is to keep an eye on the dash voltmeter and look for fluctuations that match the flickering.

Good luck.

C4TOMCAT

NHVett, thanks for the reply. question, when we disconnected the alternator and it ran off the battery, shouldn't it have stoped flickering if the alternator diodes were the culprit. it would be just running off the battery....any relays that feed a circuit common to those dash and interior areas....thanks

Bob Hovey

I just replaced the coil on my '87 to address this same problem. Someone had suggested a light flicker could be caused by a deteriorating coil. Took me 10 minutes to replace it and cost $41.00 (I get a parts discount). I believe an AC Delco coil retails for about $55.00 at the Chevy dealership.

Good luck,

Bob

C4TOMCAT

Bob: Thanks for the reply....I just talked to him and he had an msd coil on it for some time and went back to the stock one and the condition was the same under both coditions...whats the chances of two coils being faulty and breaking down. Also, he replaced the module in the distributor as well. still no differerence to the better. ah...the corvette challange..to keep em running right.

jfb

The ignition coil is not going to make your interior lights flicker. Since you have no flickering with the engine off, this points to the alternator which must be putting out a pulsing voltage waveform caused usually by a defective voltage regulator in the alternator. Disconnect the plug -in connector on the alternator when the engine is running and the lights are flickering . If the flickering stops, the alternator is the culprit because you just turned it off by unplugging it. It is possible to replace the regulator in the alternator, or you can buy a rebuilt alternator.