Thermo top Auxiliary Heater
 

I have a problem with my UK X5 2001 E53 where the Webatso thermo top heater will not turn off and drains the battery until flat. It still runs after driving and the engine is up to temperature. I have unplugged the heater for now.

I've seen other posts on here with problems getting the heaters to work but nothing to stop them from running.

Does anyone have any ideas what could be causing this to run constantly?

Thanks

I think that these devices are intended to run for time-limited cycles; I also read somewhere that BMW have changed the internal PCB to make them work on "bus"... Purely guessing here, but I'd suggest look for fault codes first, then for something like a relay sticking. Does it run with ignition off, car locked and after about 15 mins? That's when the electrics of the car are supposed to sleep.

Thanks Moments, I've tried to find a relay in wiring diagrams but doesn't seem to have one for the this heater. Yes it continues to run with the ignition off, it keeps going until the battery is flat.
I'll try finding some fault codes too.

Not sure if this helps or not but....

The Eberspacher gas heater I run in my '59 VW will do something similar if I don't have it adjusted properly.

During the shut-down cycle the heater continues to run the fan until the internals have cooled sufficiently. There's a big rocker switch with a quartz rod in there that will either turn the fan off or run it at low or high-speeds. There an adjustment screw that if tightened too much will always run the fan and never allow it to shut down

Now granted this is 50+ year old technology but it may apply to you as well.


Sent from my iPhone using Tapatalk