hi all, i just purchase a 98 Park ave. 3800 - 4t-65 tans . it wasnt running when i got it (blown engine) i put in a nice used 3800 and the car runs great. my problem is that i seem to have an electrical draw on the system when the car is off. ( i assume it was like that before as it had new battery and alternator when i got it)
so far i have identified the "BATTERY 1 " and BATTERY 2 circuits as potential issues. using a test light between the disconnected battery terminal the draw drops out some when i pull those 2 maxi fuses. next i will use a meter to measure milliamps draw on those circuits.
any ideas from anyone out there on a more specific plan?? i would appreciate it. also where is the radio antenna on these cars? my reception sucks, any thoughts?? thanks all

Have the alternator tested. A bad diode or regulator can cause a parasitic draw.

ok, so if i unhook the alternator wires i could see if the draw goes away right?

(Droidx)

Yes you could.

The antenna is part of the rear window defogger.
It mentions some info in your owner'* manual regarding it.
Generally I would start pulling one fuse at a time and see if you can find the drain down.

With regards to the antenna, does your rear window defroster work? GM undersized the connector powering the module that controls both the defroster and the antenna. This causes the connector to melt and turn in to a black carbonized blob which cuts power to the module. Pull back the driver side trim on the rear support and you will find a small black box that likely has a melted electrical connector. Most often the module itself doesn't fail, but the connection is damaged. I learned this the hard way by replacing the module and connector and having it fail a year later. The second time I repaired mine by soldering the wires directly to the module and heat shrinking over them. This requires dremeling a portion of the module case away and wire brushing the two terminals to get a solid solder joint. I also installed some insulated crimped tab connectors about 6" from the module to allow for easy removal and repair. The defroster has worked better then ever since the repair and the crimped tab connectors show no signs of melting (use the yellow ones for 10-12 gauge wire, which are sufficiently rated to handle the rear defroster current).

If you have air ride, the compressor is another area to check. If it'* not holding air the compressor can run and run and drain your battery.

Does your battery keep going dead overnight even when fully charged?


If so then hopefully this will help you chase the paracidic drain you have.
See attached images.

I thought the air ride compressor leaking would kill the battery myself, but I was told by a few somewhere that when the car is off the compressor won't run.

Find what fuse controls your power antennae and check that one, I think I read somewhere the power antennae can cause a drain, maybe from a faulty relay, I forget what I read about that now though.

the compressor does, infact run with the key off. ive been sitting outside smoking and ill hear it kick on in my dads car, which has been parked since november. we have to keep a trickle charge on it. if you pop the bottom of the back seat and pull the relay for ELC and leave it overnight you might just have your answer.

I thought it did, thanks for confirming this, I've never really sat out there all night with it hooked up, but I am doing the same as you are for your dads car, I am keeping a battery maintainer trickle charging it, if not within a few days a brand new fully charged batter will go dead and not recharge.
I have not taken the time to test and see just what it is that is draining the battery, I always figured it was the compressor since I'd been hearing it run a little more often when the car was on than it used to, even a mechanic that looked at it a while back said he thought he heard it going off a little to often.
I am pretty sure this would come from leaky air struts, I am replacing mine soon and I'll see if that stops draining the battery.


I see somebody mention a bad diode in an alternator, I also heard that a rectifier bridge can go bad, basically it will let current start flowing in both directions, which means it can start to leak current out of the battery when the car is off.
They mention it having a new alternator, if the alternator was replaced trying to remedy the same problem by the previous owner, and it still has a parasitic draw, then I think the alternator would not be the culprit.
Hope they get it figured out, I am no expert on this matter as I am still trying to fix the same problem, of course I took the temp lazy fix, and put a battery maintainer on it, which is just a band-aid really, but it works.
Eventually I intend to take the time to pull each fuse while watching for a drop in draw, before I am

Here is my temp fix for the issue, it is better than having to replace the battery every few days if the drain is as bad as mine, it comes with everything you need to quickly connect and disconnect it, I leave it under my hood on the radiator hose when the car is cool, after I get back from a trip I leave the hood up a bit, and just sit it on the air-box area, then I let the hood down easily, not closing it all the way, the charger is so small it lets the hood still come most of the way down with it there.
So far it has worked great to keep me from worrying about chasing down the drain at the moment, of course I recommend finding the problem and fixing it, not bandaging it as I have.