Battery reverse polarity 1989 260E - PeachParts Mercedes-Benz Forum

patkinson · #1 02-09-2004, 02:21 PM

Just managed to wire new battery in reverse polarity.Only lasted for about 10 seconds but smoke came from the alternator and it is dead.The following other symptoms are:

1. Hard starting from cold
2. The dash warning lights not working except the park brake light and ABS
3. ABS light stays on after start up (could be to do with the alt.)
4. Radio is dead

No fuses seemed to blow so how bad do you think it gets. Once warmed up the seems to be driving ok. I'm not sure this particular year had an OVP. If so I cannot locate it.

stevebfl · #2 02-09-2004, 06:16 PM

Should have OVP behind battery under the cover. Check the fuse on top. The alternator will need to work for the ABS light to go off, but a dead OVP fuse will also keep the ABS out.

fahrgewehr2 · #3 02-09-2004, 06:52 PM

Will a weak battery result in an ABS light? It is my understanding taht as battery voltage lowers, features are turned off automatically to keep the car moving.

Example, if one is driving in a snow storm and is constantly riding the brakes and engaging ABS, it will place such a demand on the battery that the alternator cannot keep up. ABS is then shutdown to conserve power.

Is this correct?

If this is true, in what order are features eliminated?

patkinson · #4 02-10-2004, 12:38 PM

Just sent in the car for alternator. Going to asess the damage when replacement fitted. Wondering if there is any way to prevent this scenario happening to anybody in the future. If I remember correctly at one time battery poles were different sizes.Surely Mercedes could fit a device preventing reverse polarity from hitting major components along the lines of a diode. I bet many a junior in a garage has made this mistake at one time or other.