Mercedes SLC Auxiliary Heater Problems

Sounds familiar I had a similar issue with my old BMW 5 series Parking heater wouldn't kick on, and it turned out to be a faulty glow plug like you suspect It's kind of like trying to light a BBQ with a damp match just won't ignite Before you commit to the glow plug, have you checked the wiring harness leading to it Sometimes a loose connection or corroded terminal can cause the same symptoms Also, is the error code specific, or just a generic 'auxiliary heater malfunction'

Good point about the wiring harness I haven't specifically probed that yet The error code is a bit vague, something like 'Auxiliary Heater - No Start' I'll double-check the wiring, but is there a way to test the glow plug itself without pulling it completely Or, failing that, a way to rule out the heat control unit before I tear everything apart

That 'No Start' error definitely leans toward the glow plug As for testing it, you could try using a multimeter to check for continuity If you get no reading, the plug is likely toast You should be able to test it in place Regarding the heat control unit, those are generally pretty robust It's possible, but the glow plug is the far more probable culprit Given the cost and your mileage, and the vague error code, I'd suggest a quick trip to a trusted workshop for a proper diagnostic read They'll be able to pinpoint it for sure

Thanks for the advice I checked the wiring harness, cleaned the contacts, but no dice I think you're spot on about the glow plug I'll take it to my usual workshop They confirmed the glow plug was indeed faulty Cost me exactly 440€ as I feared but at least I have a working parking heater now Thanks again for pointing me in the right direction and helping me avoid unnecessary work