Electronic Problem

[Guest]

I have a 1984 Limited Buick Regal. The car drives excellent. There is one problem with the car. It keeps shorting the battery every couple of days or weeks. I've taken it to several mechanics & no one can find the problem. I've changed the alternator & had a new battery put in. I don't know what can be done & would like some suggestions.<LI>null vsantiago@asq.org

[NTX5467]

I don't fully understand your terminology "shorting the battery". <P>If you are having a situation where the battery is continually running down (i.e., loosing charge), there is a reason for that but it will possibly take someone different than a regular mechanic to find it. It could be something as simple as a chime module that is internally bleeding voltage to ground over a period of time, a dome light switch with chaffed wiring insulation, or it could be a problem inside the Electronic Control Module for the engine that is bleeding voltage to ground. Most general mechanics are not equipped to check for these things nor probably desire to take the time as it can be very time consuming.<P>Find an electrical shop or a GM dealership that has the sensitive electrical equipment to check for "parasitic draw" on the battery. Their equipment will record the minute voltages that are still working after the engine is shut off and the car is left sitting there. In this case, it could well be a larger voltage draw.<P>Does the vehicle have an aftermarket alarm system? Many times, faulty installations can cause havoc with otherwise good vehicles and their electrical systems.<P>If it takes like two weeks for the battery to go down, it's probably something small. If it takes like a day or two, it could be something like a dome light that is staying on.<P>While you're having electrical system tests run, also make sure to get a full charging system test done. Using the better equipment that a GM dealer should have doesn't take very long, but can be more accurate than what a private shop or auto supply might have in many cases.<P>Also, be advised that a dead or very weak battery can also cause the alternator to prematurely fail--especially on the newer vehicles--but not necessarily on your more vintage vehicle. Make sure that the cooling holes on the rear of the alternator are not blocked or obstructed with heater hoses or such. Blocking those cooling holes will cause the internal voltage regulator to overheat and the alternator will not produce the amps and volts it normally would, running the battery down as the vehicle runs as the engine will be running strictly off of battery power. In some cases, there is a plastic duct that should be attached to the back of the alternator to assist the cooling, but I don't recall your particular vehicle having one. As the alternator's been changed recently, it might be good to check this normally overlooked detail.<P>Usually, when a battery "shorts", it means that the plates inside the battery are touching each other and "internally shorting out". This is an internal failure mode for the battery itself, but such failures are very rare these days in cars. That's why I question your terminology here as opposed to "something causing the battery to run down."<P>Hope this helps . . .<BR>NTX5467