226gpd

1986 IROC-305 Tuned Port-Auto trans.
Problem-New alternator and battery-
After car sits for 24-48 hours the battery is nearly dead.
Automatic hatchback closure is in questionable working condition. Sometimes it will pull the hatch down fine. Sometimes it needs a push to help it.
Pulled all underdash fuses, 1 at a time, while test light was hooked up and the light never changed.

Hooked up battery charger to boost car. Positive on + side terminal and grounded the charger on motor, where - cable attaches. When I did this I could hear the automatic hatch closure running. Removed the courtesy light fuse and the sound of the hatch closure motor would change but it was still running. When I moved the - on charger to the battery I could not hear the hatch closure motor running.
Is the automatic hatch closure motor draining my battery, even though I cannot hear it running when I park the car?
If not any ideas?? Surely I'm not the first with this problem.
Thanks in advance for anyones help.

TreeFiddy

Fully charge batt, make sure the hatch is fully latched closed, then remove the LID fuse, which runs the hatch motor. See if the problem goes away.

If that's not it, switch everything off, pull fuses one at a time and replace with an ammeter on 20A range. If you get nothing, switch to 2A range. See if anything is drawing more than a few milliamps. Try this on the LID fuse first maybe.

226gpd

#4 Deck Lid fuse..right?
Can I just unhook the hatch motor, as long as it's in the down position?

TreeFiddy

Sure, whatever disconnects it for you to test - but how u gonna unplug it with the hatch down?

Johnnygeek

sure your not hearing fuel pump?

226gpd

Battery is dead as a hammer and hatch is closed, down position. Open hatch with the key and latch cannot raise due to no power to it. The remove trim and disconnect. Will hatch still latch w/o auto pull down function?
I'm asking..I'm a Corvette guy. 1st 3rd Gen. Camaro I've owned so I'm learning.

226gpd

Not the fuel pump..thanks for the assistance though. Any and all opinions are welcome.

scottishtransam

This guy explains it pretty good, parasitic draw test.

226gpd

Thanks for all the input..Used the key to open the rear hatch..Unplugged to Pull Motor Relay. Replaced the ground cable at the battery (just for piece of mind) and did find a wire that was missing so coating and was likely arching off some metal. It was the wire that comes off the relay which the large positive alternator wire goes into...so far so good. About 48 hours of sitting and I'll know for sure.

Jim 86 IROC

I find this is a very timely and helpful thread as I have two vehicles with parasitic draw problems...

My "new" '88 Vette has a problem that I have isolated to the Bose radio.

Just a week ago I found a dead battery in my '88 IROC-Z. When I connected my DMM into the "-" batt circuit I saw a 5A draw so left the neg lead disconnected till I could isolate the cause.

I appreciate the hint about the LID fuse and will likely start with that one. If ok, then proceed to other circuits that are "hot all time".

X Jackal X

Its threads like this one that make me realise i LOVE this site SOO much. I connected my dmm this morning, found a 5A draw, disconnected the LID fuse, BOOM---> 6.66ma reading. So now I just have to find out whats ACTUALLY wrong with it, but really i couldn't be happier.

58mark

iTrader: (3)

I just removed a radio that was causing a drain. in 48 hours, dead battery.

the radio lights were on all the time, and It was warm to the touch when I removed it (the car hasn't been started in 24 hours)

Jim 86 IROC

When I went back to start chasing current drain readings were back to normal. Since I suspect the hatch pull down, I haven't opened the hatch since the problem and likely won't again till spring, when I can trouble-shoot it if the problem is in that area.

afremont

I recently had a problem where my battery went dead after 2-3 days. Took a while to find it, but it turned out to be the map light on the rear view mirror. The passenger side map light has always been very dim for some reason. I only noticed it was on when messing with the car one night because the bulb was so dim. Turned it off and no more dead batteries.

Joe Register

I have similar issue with my 85 trans am. Did parasitic draw test as in video above and traced it to 20 Amp CTSY WDO fuse which from my Chilton looks like it controls windows and courtesy lamps. I don't see any on though. The only thing I see on is the radio clock. Battery dies in about a week of no use. Its a new battery purchased two weeks ago. Help would be appreciated.

marck

Fantastic. Thanks so much!

I believe my fuel pump is running, and of course, it's an intermittent problem. It only happens in the mornings when it's cool. It's not the hatch draw, I already eliminated that possibility.

It's been in the shop for a week, and they could not find anything. Time to get out my ammeter and trace the closed circuit!