We just bought an '87 Bronco2 4wd 2.9L 5 spd tranny, new battery. It has something that slowly drains the battery when it sits for a couple of days. Is there some common things I could check out? The dome and headlights are off. The keys are off and taken out. Please let me know.

 

Try this simple little test, remove the negative cable from the battery & connect a 12 volt test light between the cable & battery.

Dim is OK, but if the light shines brightly theres a drain.

Remove the fuse links from the starter relay until the light goes out.

Reconnect the other fuse links & tell us which accesories are now not working, so we know which circuit has the problem.

 

radio? headlights as mentioned.


some idiots don't wire the radio to the ignition.. so if you don't turn the radio off.. it stays on whether the car is on or not. probably not the case though.

 

Thanks for replying!!

Cootvon, the radio has been taken out and the wires are capped off. I guess the kid who had it before me did wire it wrong. His dad said that he burned an ignition wire but I can't see any damage anywhere. It starts up just fine.

87 XLT I don't have a test light but I do have a multimeter. Do you know which readings I would get if I used this instead of the light? Also are the fuse links the ones attached to where the positive battery cable attaches to the side?

 

i got a stupid question...

could it just be a bad battery?

 

Battery is brand new. 2 weeks old

 

i knew it was a stupid question that's me!

 

Take the starter down to a place that checks them for free? all to often it can be the starter.. I've seen a a bad starter kill a new battery to usless ( and I mean needing replacement) overnight! but start the car the morning before.You can get some indication of the problem by turning on the head lights and starting the car on the battery at full charge. The lights will dim if its a bad starter or one of the cables is grounded by being burned up against the manifold, etc and the cable(s ) will get hot to the touch.

 

The positive cable from the battery is connected to the starter relay.

On the side of the relay theres 3 or 4 small wires attached, those are the fuse links which power everything on your B-2

If your multimeter reads miliamps, you can use that, if not you can buy a 12 volt test light for a couple bucks at any auto parts store.

The computer & clock will pull 20 or 30 miliamps.

Might be that you have a stuck relay or bad alternator thats draining the battery

 

Granted it's a new battery.... is there fluid on the top and sides? A clean, dry battery won't drain itself, but one that has fluid leaking from the caps and "shorting" the positive and negative posts can drain it. Also can be a bad alternator or one of the circuits in the electrical system.

 

I had this happen on mine, too. Same year, same everything. First new vehicle I ever bought and I was poor then! My problem turned out to be the power door locks. They were shorting out due to moisture. Whenever it rained or the humidity got real high, they popped up and down like crazy. Sounds crazy too, even as I write this, but I sat there overnight to find this out. I finally had the solinoids(sp?) replaced and they were good for another few years. They finally stopped working again and I thought, Fine, I'll use the key (how 1990) and no more worries. I again had the battery draining issue and they said it was the door locks again! And it took a over week for them to figure it out. So I actually had them remove the solinoids and it never happened again. I actually sold it to my neighbor in 2002 and he wanted the locks back and the same thing happened! YMMV, and this may have absolutely nothing to do with your actual issue. It was really the only major issue I ever had with my trusty old Bronco II.

 

chili7, whoa. So far, I haven't had that issue with my '87 XLT, but that's something to keep in mind. I think there were other problems found that were causing his problem, though.... but thanks for that bit of info. I'm sure everyone who has the power locks and windows will keep it in mind later on.

 

It's been a week since I replaced the light switch assembly and the multi switch. The battery is staying fully charged. Thanks everyone!!

 

I know it to late and you found your problem, but when mine was doing something similiar it was the rectifier in the alt. that was draining the battery.

 

TAKE OF YOUR FUSE PANEL PANEL REMOVE EACH FUSE AND SLOLEY REPLACE IT AND CHECK IF THERE IS A SPARJ WITH EVERY THING OFF AND SEE WHICH ONE MAJES A SPARK THAT SHOULD TELL YOU WHAT IS DRAWING THE JUSE. i HAVE A FRIEND AND HIS IS DOING THE SAME THING THAT I HAVE TO CHECK OUT THIS WAY. TONY