Battery drain overnight

[didierdelta]

Battery completely drained after recent heavy rain, car was parked nose downhill, I found the water drain under the bonnet was completely full of water which after investigation was caused by a kinked drain pipe. The battery was fully charged but drained overnight again. Any ideas what the problem may be, and where I may look to find if water ingress has shorted something.

 

[optimusprime]

Dont know where on you model that your sam modual is located but if its under the bonnet or in the boot then thats the place to look . Or even water ingress in to your fuse box itself . But you could check the out put from the alternator , the older models hed problem if regulater went toes up

 

[Major774]

You need to do some investigation work, loads of battery drain test videos on YouTube.

But a drain over night usually indicates a serious drain somewhere.

 

[didierdelta]

Thanks for all the info, dodging the rain, I have managed to check the current which is upwards of 15A, and makes an audible crack when I attach the meter leads. I tried pulling fuses and nothing made a difference. I have left the battery disconnected!

 

[Major774]

15A is a serious drain!

Should be easy to find with that big drain.

 

[Ted]

15 amps is around 180 watts. something will be getting pretty hot.

 

[didierdelta]

The car has been with my local garage for the past 6 weeks, (as I was not in a rush to get the car back and wanting to keep costs down) where they were trying to find the fault in their slack time. The reason for the power drain was down to the electric heater under the dash being switched on! The mechanic could only stop this activation by unplugging the door switches for the interior lights.
Whilst the problem of activation of the heater has not been found, at least the car can be driven and the battery doesn't go flat.
If anyone has the wiring diagram for this heater I would appreciate it so I can get a better understanding of where it gets it's power from.

 

[optimusprime]

Are you talking about the heating system or some other heater . It must have a sensor to switch this heater , on , and off, i would put that down as first place to check ..

 

[optimusprime]

Try a reset on the climate control unit first . Then if no change look at the blower fan regulator,, if faulty it wont turn off the heater .Easy fix lie on your back you will need to id the regulatir so you know the part to replacingits only a plug and play item ..

 

[Diesel Benz]

If anyone has the wiring diagram for this heater I would appreciate it so I can get a better understanding of where it gets it's power from.

More details about the car needed. I guess the car in your profile but is it a diesel? There is no electric heater unless your car is a diesel.

 

[optimusprime]

The heater poster is talking about is in the car i think and not the engine pre heater

 

[didierdelta]

The car is the one in my profile, an E320 CDI Estate, the heater is found under the dash and warms the cabin air when the engine is cold.

 

[optimusprime]

Did you press reset on the aircon panel ???

 

[didierdelta]

How do you reset the aircon?

 

[Ted]

The car is the one in my profile, an E320 CDI Estate, the heater is found under the dash and warms the cabin air when the engine is cold.

ptc heater - this should be self regulating and only on with ignition.
If it is staying on you should definitely feel the heat from it.

 

[optimusprime]

Didlier if you have air conditioning there will be a button to reset it.

 

[Diesel Benz]

T

The car is the one in my profile, an E320 CDI Estate, the heater is found under the dash and warms the cabin air when the engine is cold.

Thanks for updating the profile to include the "CDI". On a 2004 W211 the PTC heater is switched off if airconditioning is switched off. However if there is a malfunction, the heater may continue to consume a lot of power even if AC was off.