checking connection between alternator and battery - PeachParts Mercedes-Benz Forum

richard28 · #1 03-15-2004, 10:41 AM

My 88 300ce went into the body shop for some work, and I had them install euros since the passenger headlight was destroyed by the accident. Apparently they disconnected the battery when they did their work. After picking the car up, it died after about 1-1/2 hours of mostly highway driving, and I had to be towed home. I had the battery recharged and the car starts & drives fine, but the battery is not getting enough voltage back from the alternator. I had checked the battery not so long ago and it was showing a little over 14 volts while the engine was running and now it is about 11, and the Autozone meter read "diode ".

I noticed that in front of the battery there is a bridge on which the alternator leads and the positive battery lead are
attached. Since I like to make sure the little things are not the problem, could someone please describe the correct connnections at this "bridge". Any other little things to check before springing for the alternator and voltage regulator? Thanks as always.

#2 03-15-2004, 04:30 PM

Start the car and check the voltage at the back of the alternator - if it is 14 volts or so - follow the wire - you will see where it is not hooked up. If you find the other end of the wire and it is hooked up - check the voltage there - if it is the same as at the alternator - then the wire is good - if it is lower - the wire is bad. If you start the car and the voltage at the alternator is under 13 volts - get a new diode brush pak first and try it - works 80% of the time. Hope this helps
Morris

richard28 · #3 03-15-2004, 04:36 PM

Thanks, is the brush pac the same as the voltage regulator? If not, how is it installed?

#4 03-15-2004, 04:37 PM

same thing

richard28 · #5 03-15-2004, 04:42 PM

Great. Thanks again.