Have an 89 Coupe. Just took it out of storage the 1st of this month. Was running fine when stored, ran ok when I started running it again.

2 days ago it started having problems. ALL lights would keep going bright and dim. Headlights did not seem to make any difference, dash, markers, etc still flash bright and dim. Replaced the alternator with a new one late last summer and was doing fine. Start of new season so put in a new battery. Ran fine for a couple of days. At times the little battery icon on the dash will flash in sync with the lights.

Took the alternator to 2 seperate shops and got the same answer. Alternator checks out good, check your wiring system. Anyone have a good starting point or do I have to do it the hard way wire by wire and connection by connection ? :cry :(

 

What volts are you reading?

Which lights blink? you said ALL but does that include the headlights or just the instrument panel?

What about the other electrical functions?

 

The first thing to check is the most simplest things first which would be your belt. Insure that it is not slipping and that it is in good condition. In other words, is not cracking or have stretched.
Place a volt meter across your battery terminals with the engine off. Jot down the voltage reading. It should be approximately 12.6 volts. Next, start your engine and place the volt meter between your alternator (+ positive connection) and a good ground. Bring the engine speed up to at least 1500 rpm. Write down the voltage reading. It should have an output of at least 13.5 to 14.5 volts. Now place the electrical system under a load by turning every electrical device on in the car and note the reading you get. Your alternator should maintain the same voltage output. A small drop is okay but remember in order for the battery to charge and run your electrical system you must have a difference in potential. In other words, a difference in voltage. Also, insure that you have a good connection at the battery posts. Another point is and I am not sure if the Vette has one but if there is fusible link within the wire that attaches to the alternator. If there is, insure that is not corroded or it is making good contact. Hope this helps.

 

The battery symbol comes on when the alternator is not charging the battery.
One thing that could be happening is a poor connection of the battery cables to the battery terminals. I know the battery terminals should be ok since the battery is new, but pull the cables (neg first) and clean and make bright the cable lugs, check for clean battery terminals and reinstall (neg last). Measure the battery terminal voltage after an overnight rest. The voltage tells you what the state of charge is: 13 volts-full charge, 12.0 volts-discharged. If the new battery is on the discharged side, put a battery charger on it and charge it all the way up. A trickle charger won't do it.

 

Everything in the lighting circuits including the digital dash. According to the voltmeter on the dash readout it varies between about 9 volts on the low side to about 16 - 17 volts on the high side. The heater worked ok - shut it off to see if that had any effect. Stereo worked ok - shut that off to narrow down possible areas. Engine seemed to run ok, little odd but is still getting used to running. Had an earlier problem with the service engine light. Got that resolved but the engine is still in learning mode from clearing the codes. Still looks like a voltage regulator to me but 2 reputable shops say no. 1 is a local speed shop. :skep:

 

It ran fine for 2 day's 'cause it was using the battery for power and now that it's not fully charged like it was new the probs start. Check the ground contacts at both ends. Clean and check pos end at batt. Also could have glazing at brush contacts in the alt after a long storage.Faulty regulator. But check the tension on the belt for slippage like ciscokid said. What is it reading with everything on?


[Modified by sumoboy, 6:15 AM 4/13/2003]

 

Everything on or nothing but the engine the voltage jumps all over the place. Will try some clean up tomorrow, recharge with battery charger & see what happens. Have to put the alternator back on, took it in to have it machine checked. Looked like stable 14 - 14.5 volts on the test setups at the shops. :banghead:

 

One thing to realize is that the alternator may appear to be good without a load but once the alternator is under a load the truth will come out.