[86 911 Targa]

Originally Posted by RDM

All,

My battery went dead after about 10 days sitting in the garage. After getting the battery charged and taking it on a checkout run, I disconnected the negative battery terminal and connected my ammeter in between. I found 120 mA draw, which seems like a lot for an old-school car.

The wiring for the car is fairly unmolested but for a dash light fuse, modern stereo (now removed) and seat heaters.

I went to the fusebox and jostled fuses one at a time with no effect until the fourth from the back. When I pulled that one, current draw dropped to zero. The clock also stopped, and the glovebox light stopped working.

Based on what it operates, the wiring diagram says this is fuse 18 which doesn't seem to match either the fusebox cover or the counting of fuses from the front. (page 4, trace 42 here: http://www.pelicanparts.com/911/911_Parts/Electrical/911_electrical_78SC_USA.pdf)

I know that wiring diagrams isn't completely up-to-date for a 1980 car. For instance I believe the Jetronic unit under the passenger seat is also on this circuit.

Any known bad actors on this circuit? What should I look for?

Thanks.

I believe that 120 mils is very close to spec.

Check the glove box light switch.

Have a look at the specific gravity on each battery cell.

Good luck,

Gerry

pm me as needed.