hello everyone, here is the situation;

Ihave my voltmeter attached to the battery, the battery is new, and the alternator has been rebuilt and tested. Once the car is started, it takes sometimes a few minutes, and the meter reads 14.25 volts...it hovers anywhere from 14 to 14.3.

If the blower/heater controls are set to the firs setting, blowing air to the windshield, I have no control over the fan speed, it is always on full speed, always on hot. The temperature and the fan speed are not possible to change. if i want to blow air to just the feet, the fan speed can be adjusted. Some settings temperature and fan speed can be changed, at other settings, its just full heat.

When the fan is running, and the car is at idle, the voltage goes way down, 12.3-11.5 and sometimes even lower. most of the time on the highway, its fine.

So now when i drive, i am constantly watching my voltmeter starting and stopping the heater.

What sould i check? what can be deffective?

Any help appreciated!

Max

 

From the symptoms presented, all is normal for most modern MB cars. Defrost only setting places theA/C system in high speed blower only, non -adjustable as I know it, with A/C on mostly re-circulated interior air. This will present a noticeable voltage consumer condition for the battery and alternator. 14-14.3 volts is about the best you will get on MB cars, for a reading at the battery. When A/C is in any other setting than defrost, you will have blower speed control. Defrost also presents full hot and full A/c at the same time. Any other symptoms?