My old 190D (2.2L, auto trans) is causing the current owner grief (repeated dead battery) and I'm trying to help sort it.

Battery was in fact dead - starter turned for only a second or two - when I got there. (Current owner got a jump last week, took it to an Autozone or similar and it passed the load test without problem.)

I'm no wizard on electronics but this is what I found:

-Once I got it jumped and running I got 13.5 - 13.7 volts across the battery posts at idle so alternator appears to be working.
- I think something is draining the battery.
-Disconnected positive battery cable, connected one lead of my voltmeter to the positive post and the other to the postive battery cable.
- With ignition key turned off, I still get approx. 12V on my meter.
- Pulled fuses one at a time, no change, still 12V.
- There is a small lead from the positive battery cable to a fuse link mounted on the right strut tower. One lead from opposite end of that fuse link goes to the voltage regulator/alternator. Disconnected this, still showing 12V.
- There are two other wires attached to the fuse link. When I disconnect those, meter drops to zero.

So, long way to my questions:

1. Is my approach / thought process correct? With my meter connected thusly shouldn't I get zero volts with ignition key off and fuses for radio/clock removed?

2. Can anyone tell me where those last leads go? Perhaps to the ignition switch?

I'm thinking that there is either a weak short in those wires or a fault in the ignition switch. (The ignition lock/tumbler is acting up, takes some fiddling to get it to turn. I understand that the tumbler/lock is separate from the electrical switch/contacts also actuated by turning the key.)

Thanks for any suggestions if you're still reading.

Cheers, all.

Fred

Things that have killed my battery and drove me crazy. 1)glove box light staying on. 2) antenna controll sticking on. 3)turning the headlight switch to far to the left leaving the left caution light on all day. Just to mention a few. Any others out there with suggestions. Good luck with your friends car. Hope you find it something simple. RAY M

A bad alternator/regulator diode could cause it to look like charging when running but drain out while sitting, also, you should connect an ammeter in the same way you did the voltmeter, to tell you how much actual draw you have going with things off.

I seen issues with the glove box light, and the trunk light. There is little else to go wrong with these. The antenna typically stops turning (even if the belt is broken). The clock is typically not the culprit (not enough juice). I typically start by taking out bulbs.

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Jovan

'84 (11/83) 190D 2.2 5-Speed; Silver/Blue; Motor No. 00354, 402k mi (340+kmi mine)

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