Allion Parking Heater Issue

Greetings. It sounds like you're on the right track with the glow plug, considering the symptoms and error code. However, a few things could mimic those symptoms. Have you checked your coolant level recently? A leak there could definitely impact heater performance, as a car heater is not unlike a radiator. Also, has the functionality of the blower motor been recently tested?

Thanks for the reply! Coolant level is good, so I don't think it's a leak. I've also checked the functionality of the blower motor recently, it's working perfectly fine. Do you really think it can only be the glow plug, or something more sinister, like a deeper electrical fault? Is it safe to assume that a faulty glow plug is the most common issue in this situation?

Given that your coolant level is correct and blower motor functions as normal, and under the assumption that you don't see any obvious damage to the heater core, a defective glow plug is the most likely culprit. However, diagnosing electrical faults remotely is very difficult. It may be wisest to bring your vehicle to a qualified workshop for a comprehensive diagnostic assessment. It's hard to be definitive without a hands-on inspection of the electrical system.

Thanks for the help! I took it to a workshop as you suggested. Turns out it was indeed the glow plug, just as we suspected. Cost me about 440€ to get it fixed, but at least the heater is working again. Appreciate the insights!