PeachParts Mercedes-Benz Forum - View Single Post - Dim lights for the first 3-5 minutes

JHZR2 · #15 01-11-2022, 09:38 AM

These alternators don’t really put out a lot of voltage to begin with, and with cold start/low rpm/weak battery, they may not get the field sufficiently high. You may well have a weak battery and/or some parasitic discharge. The batteries in these cars are pretty large and can handle a decent bit, but if they are slowly depleted, then the alternator will get bogged down trying to pull it back up.

A multimeter with readings when the car sits, cranks, and cold/hot idles would be helpful. They sell usb chargers that go in the cigarette lighter hole and read out voltage. These are helpful when diagnosing things. Recommend you get one and take notes of the readings awhile. Report back.