1985 735i draining voltage

[metroshane]

My car is draining voltage somewhere I guess. I've replaced the alternator 3 times this year and still the battery is losing power. Auto parts guy suggested I'm drawing current somewhere...but had no idea where. Any ideas where to start?

[Bear]

Remove negative battery cable and hook a 12 volt test light between the cable and the negative battery post (it should not light up), if it lights up leve it hooked up and then remove and replace (one at a time ) the fuses from the fuse box and when the light goes out you have the culprit. Another way is to hook a amp meter set at 200ma the same way as the test light and look for voltage above the 200ma level, do the fuse trick, and when amperage goes to zero, you have the culprit

[metroshane]

Thanks for that tip.

Using your method, I've resolved that it's something controlled by fuse number 21 drawing voltage as the light goes out when the fuse is pulled. Great, except the following componants are all controlled by that fuse...

1.interior lights (how do you check?)
2. radio (disconnected power to radio, tester still lights up)
3. glove box (removed bulb...how else would you test?)
4. luggage compartment light (removed bulb...how else would you test?)
5. rechargeable flashlight (huh? what rechargeable flashlight?)
6. seat belt buzzer (unplugged seatbelt buzzer)
7. on-board computer (how do you check?)
8. radio memory (see #2)
9. clock (what clock? how do you check?)

Some points of interest.

-radio does not hold memory
-battery light on speedo cluster is dimly lit
-new alternator
-new battery

What now?

[Bear]

For interior lights, disconnect the electrical lead to the light. Glove box flAsh light, some cars had a flash light that sat vertically in a holder in the glove box. I had a defective interior light (above mirror) switch, and disconnecting the eletrical lead solved my problem. For any electrical light, disconnect the lead and see what happens.