Have a 87 with 78k on the clock. If I leave the car parked for over 2-3 days battery goes dead. Replaced Battery (twice). Pulled every fuse out and there is still a draw of 6 volts off the battery. when I put the fuse for courtsey circuit in draw jumps to 11 volts any suggestions can not find a short anywhere..know there has to be one. Making me nutz. BTW with all fuses out and dist unpluged no draw on battery.
Any suggestions
Guy

 

I would install a manual battery disconnect and disconnect it when the car is going to sit for a while (until you find your problem), you will loose your radio settings and clock every time you disconnect, but that is better than dead batteries. The next thing I would do is get an amp meter, remove your battery, behind the battery is a junction terminal, all it does is connect several wires together, one of the wires from your pos bat cable goes here. Disconnect all the wires so none are touching and see if you have a current draw with the wires disconnected (I believe they supply power to most of the car) If you have no draw, then connect one wire at a time to the wire that goes to the bat cable and check for a draw, repeat until you find the wire, then you will have to disconnect everything that wire supplies until you find the problem. If you have a draw with all the wires disconnected, check your bat cables (could have corrosion inside), starter, and I think there is a wire going to your heater blower connected to your starter wires. You could also check your neg bat cable ground connections to make sure they are not rusted. This will take you a while, but should get you pointed in the right direction. I think the max draw is 50ma with everything connected, but is has been a while, so any wire over that would be a problem.
Good luck.

 

Which statement is correct?



The extra 5 amp draw is normal. The interior lights draw about 5 amps when you reconnect the battery terminal. You need to wait for the Courtesy Lamp Delay timer to time out.

Normal current draw should be less than 50 milliamps. It appears you have an unkown 6 amp. draw.

There are many circuits that are only protected by fusible links so lifting fuses at the fuse panel may not find the problem.

Example.
A fusible link supplies 12 volts for Oil pressure switch, Fuel pump relay, Mass Air Flow Burnoff relay, ECM and Mass Air Flow Sensor Relay.

A fusible link supplies 12 volts for Blower Relay (manual A/C), Blower Control Module for (C68 A/C).

Two fusible links suppy 12 volts to the Alternator.

Two fusible links supply 12 volts to the Headlight Control Module.

One fusible link supplies 12 volts to the Headlight switch.

One fusible link supplies 12 volts to the Coolant fan relay.

One fusible link supplies 12 volts to the Auxiliary Coolant Fan relay if you have that option.

There is a cable that goes direct from the Battery to the Starter. (Has no fusible link).

One fusible link supplies 12 volts to the Modulator Valve.

So if you still have a current draw of 6 amps with all of the fuses and circuit breakers out, the problem must be with an item powered via a fusible link and not protected by a fuse or circuit breaker.

Look behind and below the battery and you'll see a bunch of red orange wires. Those are most of the fusible links.

 

Check at night for lit underhood lights, vanity mirror lights, and the center console compartment light. Do you have a radar detector, aftermarket alarm, aftermarket audio amp or radio? Check em.
Behind the battery is a bolt with 8 red wires on it and all of them have a fusible link. Remove the nut and connect your ammeter between the bolt or the positive battery terminal and see if there is any current being drawn. Also, there are a number of circuit breakers that protect some circuits. Some members have found one of their seat adjust switches stuck on and a warm seat motor. Good luck.

 

Unless it was a typo, when making battery drain measurements, you need to insert the Digital Multi Meter (DMM) leads between one of the battery leads and that battery terminal with the DMM set up to read Amps and initially on the highest scale.

Then pull the fuses one by one, noting the drop in current draw.

Of course you need to make these measurements with the underhood & interior lights Off. Block the door switches so that the interiors stay off while you are in/out to pull fuses.