wrich10345

WHAT ARE THE MOST COMMON CAUSE OF BATTERY DRAINS. THERE NUST BE A LIST FROM THE MOST COMMON TO THE LEAST.
I HAVE TRIEED TO USE A METER BUT THERE ARE MANY FUSES THAT GO TO ONE ITEM. THANKS

Fatz

I can't point you to a list but; if your battery is losing the energy to crank the engine after sitting for a short time or losing the energy to keep the engine running it is more likely due to the battery itself. There may be a way to check your voltage via the driver menu of the 500.

Search on voltage for W209, as I recall Rodney giving the battery voltage range. This can be checked with a meter across the battery terminals (or ground to battery +) or via the driver menu.

IMO, anything drawing enough current from your battery within 6 hours (excluding headlights) to keep the car from starting is going to be quite hot or crispy (in which case the drain will cease).

wrich10345

it can take a week of sitting to make the not to start. the voltage s.g. test shows that it is very low and needs a charge. also I had the battery tested at interstate battery for a week and they say it is ok . it is only 2 years old. It has to be a small drain. what I am looking for is the most common cause .

Rudeney

Check the overhead control unit (i.e. dome light panel) for any noises after you shut off the car. There is a fan in it that is used to circulate air across a thermometer for the climate control. I have heard of the OCP failing and causing this fan to run continuously.

wrich10345

Rodney I can not hear anything but how do you ge3t to the fan to see if it running.
also what is ocp.
thank you wayne

Rudeney

OCP - overhead control panel, i.e. where the dome light is mounted. There is a small vent on it and the fan is behind there.