As a cosmoline-covered newbie I'm still learning local etiquette, so if I should have started a new thread, please let me know.
Thanks for the very detailed, clear instructions, jrmd01. I believe I'll need them if my diagnosis is correct.
I just bought an '88 300e. I've spent a lot of money fixing it up and it has been well-worth the effort. But as I fix things, there seems to be a cascade of processes or devices that were non-functional but hidden by the general fault of the larger system. Hope that makes sense.
For example, I just got the A/C working. I live in S. Louisiana, so I'd rather have a good A/C than four tires. FYI, the mechanic did a complete system flush and replaced various doodads and a leaking coupling before changing to R-134. I know it gets mixed reviews on this forum, but I'm a greenie and gotta stay true. The A/C gets the car cold enough for me and slows its fan after about 10 minutes after sitting in teh parking lot (this June as I write this note).
However, the load of running the A/C seems to drain the battery faster than the alternator can recharge it. It was dead as a boudin next morning. I jumped it off another car and it ran flawlessly, but I didn't run the a/c. It started fine after work for the (hot) drive home. When I switch the car "on" but before engaging the starter, all of the idiot light come on. When I start the engine the lights go off and then the engine catches quickly and one idiot light stays on--the washer light. I'm almost certain that's an unrelated problem--the sucker doesn't work even though over half-full. I can drive all day and run the windows up and down and the sunroof open and closed without affecting restart.
Using my VOM, I get about 12.5 volts at idle but don't know about amps, no ammeter and I don't recall exactly how to make a shunt...its been 30 years since I worked with electricity.
Is there a way to determine for sure whether my problem is the alternator?
Thanks for your guidance.