C220 CDI Heater Booster always running

[biltong11]

Hi

I am having a problem with the heater booster on my C220 CDI W202 (W Reg - 2000). The heater booster seems to run all the time. I can park the car up and go out three hours later and it will be running. I can feel the hot air from the little exhaust under the front right bumper and smell diesel. I have the system Off on the centre console (light in the switch is illuminated) but it makes no difference.

This problem seemed to appear only after I had all four tyres changed and alignment done last week. Before then it was fine. (Since the tyre change I also have the BAS ESP dashboard on permanently.) I am taking the car back to the garage as the alignment seems to be a little off, and I believe this could cause the BAS ESP lamp to come on.

So, help! Any ideas on the heater booster? How do I turn it off. I don't believe I need it - the outside temperature is currently in the mid teens so I'm sure it's not required.

As an extra point, I have also noticed the engine temperature never seems to get above 50 degrees. It has been like this since I got the car a few months ago, but not sure if this has any bearing on the problem.

Thanks for any assistance...

 

[Tinkerer]

From memory the heater booster should only run when it is below 6C outside and the engine is below 40C, not too sure if it also operates under these conditions with the engine off and the 'rest' button pressed as it is, I believe, mainly to get the cabin warm quicker. The engine should definitely run at 90C so you probably need a new thermostat. Can't really see why all this should be caused by tyres and alignment unless they damaged some wires along the way. Good luck

 

[biltong11]

Update: Some drama and some success.

After taking the car back to get the wheels balanced again and fix the alignment (I could feel it was out) the BAS ESP light has gone out. So that was definitely linked to the alignment.

I had the car looked at by an Indy and had the car serviced and the thermostat replaced. I now get over 80C on the engine every time I drive, so happy with that.

HOWEVER... the drama with the heater booster has hit panic level. I thought it had corrected itself as I didn't hear it running for a few days. However since the service it has been on again, and this afternoon after not using the car for 2 days the battery is so low the engine won't even turn over. It has been about 25 deg C the last three days and the heater booster has been running during this time. HELP! What can I do.

I am happy to cut wires to thes thing to stop it running. People have said I should pull fuses, but which? All the fuses appear to feed multiple items, so that may not be so simple.

I am now desperate, as I have to go to Somerset in 2 days for a funeral, and I can see myself stranded somewhere and not being able to get anywhere...

 

[Tinkerer]

Sorry billtong11 I lost track of this, I would suggest that you get this to a good Indy asap and unfortunately cannot help with your area. I am hoping that you have already done this and found a solution.

 

[biltong11]

SUCCESS! - well, sort of.

I have jut returned from Somerset, and in the past week the heater booster has not come on at all. What have I done? Jolly good question! All I know is that the booster hasn't run since I removed the battery to charge it again. Perhaps removing the battery has reset something.

So, I am happy for the moment. Thanks for showing interest.

Cheers.