MYSTERIOUS BATTERY DRAINAGE
 

Hello Several months ago My MB 300SDL would't start. So I charged the battery up went to
Auto Zone because I had purchased it there They checked it said it was okay. So my
brother-in-law and I checked everywhee to if something was left on; even got in the
trunck but could find nothing. Last night went to drive it again and it wouldn't start(it
had been sitting for apprx. four days). I wouldn't appreciate any suggestions or advice
on how to solve this mystery!!! Thanks John

RE: MYSTERIOUS BATTERY DRAINAGE
 

Does you car have the ACC Servo Hvac system? My W107 79 450SLC does and a open circuit inside the servo, kept on draining the battery, It took a while to track down the fault, but I sent for repairs and sure enough that was were the battery drain came from. How is the heat and or AC working?

RE: MYSTERIOUS BATTERY DRAINAGE
 

Allan Thanks for the reply.I have no idea where to find the ACC Servo Hvav sys! Can you
tell what it is and where do I find it? The a/c and heater work. 87' MB 300 sdl thanks
John

RE: MYSTERIOUS BATTERY DRAINAGE
 

According to the model and year, on a W107 and W116 is located on the passenger side under the hood close to the firewall and has heater hoses in and out, nest to it is a round and about 3 or 4 inches tall preheater with a hose from the engine going into it and then into the servo, also the servicd has a black plastic top. On the W123 it is the same piece and is located toward the front of the enginer about three quarter of the way up0 and has some long hoses going back to the blower housing and also the black top. Also, there are a bunch of vacumn hoses plug into into it and an electric connection below the vacumn hoses. I could post a pix of it but I don't seem to be able to on this forum. I can email you a pic if you still can find it. But as soon as you see the black top and the hoses you have found it. there is really no way to test, for the battery drain, you will need to send it out to be fixed. I can supply info on who to send it to and it is guaranteed for a year. Let me know.

RE: MYSTERIOUS BATTERY DRAINAGE
 

Thanks Allan again for the info; will check it out as soon as it warms up(40's is cold
to us in S. Tx) JGray