Electrical problem - '91 Caprice

[GMTruckGuy74]

A coworker of mine asked me if I knew anything about Caprices and electrical problems. I told him that I'm no mechanic, but know plenty of people online that I could ask (um, that means you guys!).

He has a 1991 Chevy Caprice with the 305 V8. He was given this car by his uncle about 7 years ago. When his uncle owned it, right before giving it away, the radio was replaced due to being shorted out. John, my coworker, had to replace the radio again about two years after he got it. The first indication of an electrical problem (other than the shorting of the radio) was that the door locks would hum & vibrate - until he turned the car off. The latest issue he has is that his car battery keeps dying; when recharged, the charge holds for about 30 hours and then dies again. His mechanic has checked the ABS system, power door locks, and radio system looking for a power draw - but nothing.

The reason he asked was that his son just turned 17 on Monday and he would like for him to have the Caprice as his daily driver. Until he can get this electrical issue resolved, his son will only be driving when John's car or his wife's car are available (and you know when you're 17 with a driver's license, you want to be able to drive ALL of the time!!!).

Any advice or technical help will be greatly appreciated by John!

[AAS]

I don't have a solution, but I can add to this...

Our '92 Olds Custom Cruiser (Caprice station wagon) also had electrical problems. The door locks would lock/un-lock, the interior lights would flicker and the radio would short while driving. The dealer never found out what was up... I wonder if it had to do with the remote keyless entry, considering it seems to effect the door locks?

[GMTruckGuy74]

Since you mentioned the Remote Keyless Entry (RKE) system, I remembered that he said his mechanic stated the door locks will do that when the system goes bad - so he disengaged the RKE system and John has to use the actual key to unlock the doors and trunk. He said the door locks don't hum/vibrate ever since his mechanic did that. However, something is still drawing power that kills the battery.

[AAS]

Since you mentioned the Remote Keyless Entry (RKE) system, I remembered that he said his mechanic stated the door locks will do that when the system goes bad - so he disengaged the RKE system and John has to use the actual key to unlock the doors and trunk.  He said the door locks don't hum/vibrate ever since his mechanic did that.  However, something is still drawing power that kills the battery.

177954[/snapback]

Interesting... I wish they had figure that out with ours, then maybe I could have fulfilled my dream of "pimpin" the Custom Cruiser. I really wanted to turn it into an Impala SS wagon!

[CARBIZ]

Interesting. I had a '91 Caprice wagon (factory ordered new) that I wrote off in 1997 with 240k (144k miles) on it. Best car I ever had, BUT it also had a weird electrical problem, including the wipers that would very rarely not shut off and do a wierd little dance for a couple minutes. The power antenna went nuts on a cross-continent trip to Vancouver and had to be disconnected in South Dakota. I suspect that problem had more to do with the accumulated salt and crap on the antenna from extended exposure to Ontario.

All of those problems were on a relatively new vehicle, though. Fifteen years old, wow.

[76ChevyTrucker]

Easy test here. To check for a power draw, or possibly a bad battery. Go drive the car for a while, then park it, disconnect, the battery cables for the 30-ish hour period. After that, reconnect them. If she fires up like nothing happened then you've got something (could be the trunk light, or a light in the dash somewheres, or something like that drawing power). If she doesn't fire, I suggest looking into buying a battery.

[tipsy420]

The radios shorting out is very weird what is in it now aftermarket or did they buy a stock radio because aftermarket have a fuse right on the back of the radio to prevent it from burning up as easily? The battery dying after 30 hours could indicate a bad battery if the electrical system was checked for any draws already and nothing was found to be at fault. I don't know if its like my 2000 intrepid that when my battery was on its last leg it would only hold a charge so long and the power was inconsitant and would cause some excessive noise from door locks as well as alot of other clicking sounds in the dash, just a thought hop you can help them get it fixed

[FAPTurbo]

Must be Poltergeists...

Better ring these guys up.

[2005 EquinoxLS]

Definatly check the trunk light. I had that problem on my Bonneville. Couldnt figure out the fact that if I drove it every day it worked fine but leave it sit for a week then it was stone dead. I replaced the battery, rebuilt the alternator and a few other things. All it needed was a $12 trunk light switch.

[DBeaSSt]

Sorry I've just seen this thread. Have you (or your friend rather) located the problem yet?

The 91-3 B-Bodies used a TRW keyless entry system which is quite prone to failure. I'm working on restoring my 92 Custom Cruiser and am on my third unit just trying to get a working one.

You mentioned that the system was disengaged. Was the control unit unplugged or just the fuse pulled? I ask because to really eliminate the problem if the remote module is bad, it should be unplugged rather than just pulling the fuse. Don't ask me why but that's been my experience.

I don't know much about the radios in those units so I can't offer any help there, sorry.

Good luck!

[NOS2006]

I hope someone had the sense to check the alternator...?