Auxiliary heater malfunction on Mercedes SL

Sounds frustrating I had a similar issue with my SL The parking heater wouldn't kick on, and it turned out to be a faulty glow plug as you suspected Did you check the wiring harness leading to the auxiliary heater Sometimes a loose connection or damaged wire can mimic a defective glow plug Is the heater core warm when the engine reaches operating temperature

An intriguing suggestion Checking the wiring harness is something I had not yet considered When you experienced this similar issue, did the diagnostic system specifically flag the glow plug, or were there other seemingly unrelated error codes present And about the heater core, are you suggesting feeling the temperature of the heater core directly How easy is it to access

The diagnostic system was pretty specific about the glow plug on mine It could be a hassle to get to, so I brought it to the workshop They were able to confirm the problem quickly If you're not comfortable poking around under the hood, that might be your best bet

Ah, a definitive answer Thank you Your experience has emboldened me to face the music and seek professional assistance I shall entrust my SL to the capable hands of a trusted mechanic As it turns out, the fault indeed lay with a defective glow plug, just as we suspected I am now 440€ poorer, but at least the auxiliary heater is purring contentedly once more Your insights were invaluable in guiding me towards the correct diagnosis I am most grateful