1989 300E with 190K miles. I have had recent problems with my battery going dead. Three months ago my battery died. About two weeks after replacing the battery, the car would not start because the battery was dead. I replaced the voltage regulator (and it really needed it).

A month later, the car had not driven for about 1.5 weeks. When I tried to start the car the battery was dead. I was going on trip the next day (Monday), so I just charged it. On Mondya i had no problem staring the car and driving to the airport. On Thursday night when I returned to the airport, the car started fine.

Today I tried to go somewhere and guess what .... The car had been idle for about 6 days.

Based on posts here, I put a amp meter inline with the positive terminal of the battery. When I first connected the meter, it read .33 Amps, then settled down to .11/.12 Amps. Determined this was the CD drive in the Head Unit. Then I started unplugging fuses. When Fuse 9 is unplugged the current drops to .02 Amps. I am guessing this might be normal.

Fuse 9: "diagnostic term.6, hazard warning system, clock, front roof light, radio, vanity mirror light, relay comfort circuitry term. 86.

I know what some of these are. Here is what I can check:
* hazard warning system: all lamps/lights are off
* clock: seems to work
* front roof light: working normally. comes on and goes off normally
* radio: unplugged head Unit with no change in the current draw (except when first plugged in, a temp spike in current while the CD drive does it thing).
* vanity mirror light: one of the roof brackets was broken (anyone know how to get a new one?), and the other is not on.

I am not sure what to check at this point to find what is causing this current draw.

One more piece of information. When Fuse C is unplugged, the current increases by .16 Amps and a relay in the Fuse box is activated.

Fuse C: "rear roof light, trunk light, rear door locking system, safety belt handover arm, seat back arrestor, central locking system, door lights, reading lamps, aut. antenna, control unit seat adjustment"

Any help or suggestions would be appreciated.

Thanks.

Have you been able to figure this out? I am having some issues with Fuse 1, C, and 9. In fact, fuse C kept going out so I used a blue one instead of red (25 as opposed to 16). This worked at first, then blew C, 1, and 9 and when I put in a new blue fuse in C, it caught on fire in an instant. Any idea what's happening here?

Is this problem more apparent when the car is left alone in colder climates? I have a similar problem on occasion when the car is left in the cold for a few days, I wonder if a heated mirror option could be tricking me and only turning on when its cold....turn key......click........grrrrr

My issue turned out to be the Cell Phone Module in the trunk. This was drawing the current. I removed it and solved my problems.

Caught fire? Oh my! Leaving a red one in there could cause a fire wherever the short is.

Is this the same year and model of Mercedes as Jeffs?