oskarmoon1
Mercedes CLK Diesel Preheater Issue
4 comment(s)
oskarmoon1 (Author)
The fuses are fine. Where is the heating module located?
pia_lange1
It's usually near the engine, often on the inner fender well or close to the ECU. Since you suspect the control unit and the symptoms point to it, it would be best to get it diagnosed properly. A workshop visit is recommended.
oskarmoon1 (Author)
It was a faulty connection at the preheating control unit. The repair cost 95€. Thanks for the help.
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pia_lange1
That sounds like an electrical fault in the vehicle heater circuit. I had a similar issue with my old Audi A4. The heating module connection was corroded. Check the cable and plug going to the car preheater control unit. 'Preheater' is another term for glow plug system, which helps diesel engines start in cold weather. If the connection is bad, the control unit might be falsely signaling the glow plugs to stay on, hence the smoke. Have you checked the fuses?