More electrical problems

[Dan O.]

When it rains it pours. While E420 #1 is down with lower harness repairs #2 just started dishing out battery/possible alternator issues. Part of the problem is that #2 is primarily my girlfriends daily driver, let's just say she may not be as perceptive as I am when quirks develop.

As we left to an appointment late this morning the starter cranked very slowly, I figured if the battery was on it's way out a nice ride on the freeway would get the voltage up at least temporarily. I dropped off the girlfriend and left to run errands, this time the starter seemed to crank even slower. My next stop was the closest auto parts store where they could do a quick test.

Seems I need a new battery (sure), which is pretty much what anyone testing a partially charged group 49 will tell you. I had the guy check the alternator output which was just over 11 volts; seems like a charging issue to me.

One puzzler though, if I'm getting low alternator output shouldn't that trigger the light on the dash? No dash lights. I left the parts store with their cheapest battery to have as a back-up; this gave me enough confidence to continue on running errands for the next hour and a half. Three separate start and restart cycles w/o incident; if there is a charging problem it seems like it may be intermittent.

Picked up the girlfriend, drove from LA to Pasadena running the a/c, made two more stops before heading home and didn't get stranded. Now that I'm home where should I start?

 

[gerryvz]

Did you check your dashboard battery light with the key in the ACC position to see that it's working?

Assuming it is the charging system....it may be that your battery is OK, and just weak because it hasn't been getting charged.

It's likely that it's your voltage regulator rather than your full-on alternator. You can get the part cheaply from AutohauZ. It's not a bad replacement job.

 

[Dan O.]

Been much too busy with work to fix either car yet, I did get a fully charged battery in car #2 though. Alternator output is only contributing .2-.3 volts (!) on top of battery voltage, no idea why this is not triggering the dash light. Picked up a new Bosch regulator from my local parts guys and found Gerry's thorough write up here:

http://www.500eboard.com/forums/showthread.php?t=4752

Hopefully all will turn out well tomorrow.

 

[Dan O.]

The best thing about a clean undercarriage is that you don't end up getting pelted with bits of crud when working from down below, both my cars are overdue for a cleaning. I was hoping I'd be able to change out the regulator without removing the alternator, unfortunately there's just too much stuff in the way. Getting the alternator out was the most time-consuming part of the job, removing the black cover and replacing the regulator itself was done in no time. Total time involved was just over 1.5 hrs, charging voltage at the battery is now at 13.5, old regulator brushes were just about done.