Benzos4theteam

ok guys my 2001 c320 has problems starting up, i know i typed a lot but read it an give me some input.

if i leave the car parked for more than 5 hours or (overnight) the battery loses charge and won't start.

i have one of those microchip keys usb looking thing so i put it in and it doesn't even move, at this point i pop the hood give it a boost and then the car will start.

1) at first i thought it was the battery , but i went to go get it tested and the tester said "battery good, needs charge"

so its not a faulty battery afaik? and of of course i keep having to give it boost for the car to even start up.

2) while my gf dad fixes the head gasket (almost done) i told him to remove the alternator to get it checked out, i took it to 2 different place and they told me the alternator passed all the test.

so it not the alternator..

so now what do i do?

it doesn't feel like its the starter because it doesn't take forever to crank or turn on. if the battery is charged in one try the car turns on right away.

but for some reason the battery is losing charge?
can anybody give me some advice , please and thank you

the guy gave me advice to disconnect the battery after a drive and see if when u reconnect it in the morning will it start? if it does still work then the car is making it lose charge , if the battery still doesn't hold charge even while being disconnected then its the battery itself.

he said that it could me something inside the car making the better lose its charge (light or something) ?

but i always make sure all lights are off , the only thing that does stay on is the faced lcd in the middle of the gauge. but thats about it, and even that after like a couple minutes it turns off.

so yeah any advice?

TexFinn

Do a search for "power seat module" and you'll find info on one of the most common culprits for battery drain. I'd say that's a good place to start.

Glyn M Ruck

Seat modules not going to sleep or A/C sniffer fan in the overhead console not going to sleep.

Moviela

I agree, you will find the answer under the seat. Unplug the modules, charge the battery and call me in the morning.

kirax2

+1 what they all said, seat control module,

benzzo21

had the same problem start with the seat module try both of them just unplug the seats both side if not try the cluster speedometer if that dont work o well sorry bro

robertmb

I had this problem for many years and multiple visits to the dealer would not solve it. I do have an intermittent passenger seat but that was not my solution. After going through 2 batteries and an alternator (warranty) and on my 2nd portable starter battery (I wore out the first) I found the solution.

A test at Advance Auto parts accidentally showed a resistance in the battery ground strap. I bought a similar replacement off the shelf there, the guy put it in and my car has not drained down now for over a year. In the end, it was this short thick chunk of very basic cable that solved a multi-year headache.