I have a 1987 and have a new battery installed, I checked all connections and all are tight. I recently hadn't started the car for about 3 weeks as I was away on buisness. when I returned the battery was completly drained. I brought the battery to the shop where I purchased it and they had to recharge it as it was completly drained. Is this a common fault or could it be something more.

 

3 weeks does seem to be a bit short, in terms of time. However, these cars do have a fairly heavy parasitic drain and do indeed kill the battery if not run for some time. What works for me is keeping the car on a Battery Tender (Tm) when not in use.

 

Hi

You need to check out components which could be causing a drain on your car electrical system. Have you added something to your car?
The Allante, like any other car manufactured by GM, was designed for the end consumer. That said it was designed along the same lines as any other GM vehicle. This would include the complete Cadillac series (Limos funeral cars etc; cars which have a great deal of electronics on board which must be maintained by "parasitic" drain). The Allante has a standard "parasitic" drain. If not this problem you experience would be wide spread and there would have been a TSB or recall of some form to address it. I have left my '91 Allante go unused for extended periods, no problems; a friend of mine leaves her 90.5 Allante go unused for six months at a time...no issues at start up. You should be able to do the same. If you continue to have issues I'd have the battery rechecked after you have verified the integrity of the charging system and accessory load configuration.

Hope this helps

Bill

 

I've owned my '87 since '92 and have just experienced the battery drain.

I disconnected the neg. battery terminal and with key out , connect a milliammeter between neg. batt terminal and the disconnected cable. You may verify excessive drain. over 50 milliamps. after 6 minutes. Then proceed to pull each fuse until you see a big drop. I found fuse #8 cps(central power supply) 20a fuse. I'm now trying to see what may be culprit in that circuit. Mine goes down in about 6 days and never did before.

Good Luck ,
Chuck
KC,Mo.

 

I had this problem with my 1993 Eldorado... "parasitic drain". After years of trying to find the correct relay, and tracing the wiring I finally gave up and installed a battery cutoff switch. Now I sold the Eldo and got a 1990 Allante. It already had the cutoff switch installed. I find that if I don't use the switch , the battery is okay for a fw hours, but not sitting overnight. I use the switch all the time. Batteries aren't cheap to replace anymore!