I have a 2003 Coupe - A4 and I am having real electrical gremlins. The first item, which may be taken care of was the loss of brake lights and rear directionals, but the second just popped up today. When taking a test ride (latest brake light repair attempt) I stopped at Harbor Tools for their free flashlight offer, and when I got back into the car it would not start. As soon as I put the key in the ignition I knew I was in trouble because the memory seat did not move and then noticed no interior lights. I then turned the key and only got one click, just like a dead battery and noticed the clock was reading 1:00 instead of the correct time. I attemped to remove the Ign Relay from the fuse box under the hood, but it seemed OK and not hot so I swapped it with another. The car did not start or act any different on a restart attempt so I replaced both relays back into their correct position, and now the car started and I drove home. After pulling into the garage I tried another start cycle and it worked fine, in fact even my Twilight Sentinal worked but all of a sudden the headlamps went out, but not retracting, and nothing again!! I removed the battery cables and found the battery at 12.83 volt with a DMM, but when connecting the battery cables back up, the same test now yielded 3.xx volts???? Can anybody offer any advice on "what to look for or at"????

 

Check your grounds and the acordians in the doors-I just had my drivers door act up this week and tracked it to the drivers side acordian. I got all kinds of codes, the memory seat would not work and the window buttons/locks on the drivers side were flaky.

 

Try this....
http://forums.corvetteforum.com/c5-t...ch-repair.html

Bill saves us again.....

 

The LOW voltage on the battery terminals sounds like something to investigate further. I do not know where you were reading the voltage from exactly when you got 3 volts.

3 Volts would mean that the battery is failing OR you have a really poor connection somewhere. What are you torquing your battery terminal bolts to???? 97-2003 C5 Battery Terminal bolts must be clean and tight. Torqued to 11 ft/lbs. If you can move the cable/battery terminal on the battery, it is NOT properly connected or torqued.

Any time you have a battery voltage issue, you can read the B+ BOLT on the engine compartment fuse box to ground. That will give you the output. Then compare that reading to the actual fasteners that secure the cables to the battery.

Ive seen corrosion and poor connections cause significant differences between the bolt and what comes out of the battery cable.

Make SURE that the terminal crimp connection under the red and black plastic terminal covers are not burnt and or corroded.

BC

 

Bill, when I got the 3 volt reading the battery cables were connected to the battery and I took the reading off the cable bolt heads and the 12.8 reading was with the negative disconnected, then the probe on the pos cable bolt and the neg battery terminal.

 

That would indicate that your red top is TOAST! Get it fully charged and then test it. Sounds like it has a bad cell.

BC

 

The battery is evidently not the issue as it load tested better then factory specs, and it's powered my other vette since the 16th of the month without issue. On the other hand, the battery that I took out of the other vette, which is in the 2003, has worked fine and the problem has not re-appeared since the one day. All the wire connections seem good, and the fuseable link lines are not burnt and I've driven it for about 80 miles since without issue. I'll just keep driving and hoping it does not happen again and renew my AAA membership I guess.

 

That would tell me that your battery connections were not good. I've never been a fan of the GM front post connection. I've seen numerous failures over the years. Top post not so much. That's not to say both don't require proper installation and maintenance.

 

My GM battery failed at the positive post. One day the car wouldn't start and as I was checking the terminal connections the positive cable came off the battery with a slug of lead still attached! Good riddance to that thing.

 

However, if the same battery cables & connections (both clean & tight by the way on the opposing cars) then the cable connections should not be an issue. The connections, being clean and tight, where the first items checked, and they were fine. The mysterious thing is that it has not happened since, and I try to use the car every day, even if only for a short trip.

 

Ok, once you know the possibility exists, I grant you, it's easy to rule out. I only emphasized it because it's a common failure mode that could give those symptoms and would be easy to overlook if a battery post connection were just beginning to fail. My battery was obvious because the entire terminal pad separated from the battery.

 

That same thing happened to my 94 but it was an easy find as that car was dripping acid...wish I kept that car