1978 300CD - Alternator has been bench tested by Auto Zone, and they say it is working fine. New positive and negative cables. Battery light on dash flickers. Battery will completely run down after 2-3 days. What else could be causing this not to recharge properly?

 

Does your alternator have an internal or external voltage regulator.

When we suggest its the alternator we include the voltage regulator as part of the system.

Did autozone check the voltage regulator. I guess not!

If it is not the alternator then you have something drawing quite large current when everything is off. You need to connect an ammeter in series with the battery terminal to determine what the quiescent drain on the battery is and then determine what is causing this.

I still go for the alternator.

Stuart

Stuart.

 

My problem is similar. I believe I have narrowed the problem down to the drivers seat control module. I have an additional problem that I wonder if it could be related to the seat module/battery issue....my sunroof isn't working properly. When trying to open it, each time I push the switch to the open position, the sunroof moves about an inch and stops (to get the roof open, I have to push the switch over and over about 20 times). Also when closing the roof, it goes beyond closed and "pops up".

I have not replaced the seat control module yet and I know that both the seat control and the roof control connect through the SAM in the left rear (in the trunk) according to the wiring diagram.

Could the bad seat control module be affecting the sunroof?

Thanks.

 

So what is wrong with the seat module/control. Seat movement doesn't work, only some functions or what?

The sunroof problem may be due to current overload caused by sticky (inadequate lubrication) slides. The auto current sense stops the motor to prevent wiring overload but more importantly something getting trapped in the opening...someones head or whatever!

Stuart

 

seat control module drains battery when left connected and car not driven for 8-10 hours. Common problem with this car.