Tahoe Auxiliary Heater Not Working, Common Fix Guide

Had the same problem with my 2014 Suburban, definitely a pain when the car heater acts up! I've got some experience working on GM vehicles. The glow plug in my auxiliary heater was toast, which caused similar symptoms. Initially thought it was the blower motor or temperature sensor, but diagnostic testing pointed to the glow plug. Had the dealer's workshop handle it since the auxiliary heater system is pretty complex. Total fix was around 440 including parts and labor. The ventilation system worked perfectly after replacing that part. No more error codes or heating issues. What's your Tahoe's mileage? Any other warning lights or symptoms besides the heater not working? Knowing these details would help figure out if you're dealing with the same problem.

Last service was at 102710 KM and they did check the climate control system, but somehow missed this issue. Thanks for sharing your experience! The auxiliary heater error started showing up about a week after that service. No other warning lights active on the dash. Based on what you're describing with the glow plug, seems like that could be my exact issue since the symptoms match. The heater core and rest of the ventilation system seem fine since I'm getting good airflow, just no heat. Really helpful to know the price range too, was worried it might be a much bigger repair bill. Think I'll have the shop diagnose it properly rather than trying to tackle the auxiliary heater myself. Don't want to risk making things worse, especially with winter coming up.

Good call on getting it professionally diagnosed, especially with the auxiliary heater system being pretty integrated on these models. My repair actually turned out to be a good investment since fixing it early prevented damage to other heating system components. Just make sure they specifically check the glow plug and control module while diagnosing. My mechanic initially missed checking the glow plug during routine service too. The auxiliary heater symptoms can sometimes be confused with general heating system issues, but the error code usually points right to it. The timing of your problem starting after service is interesting, similar to what happened with mine. One thing to watch for: if you notice any sweet smell or see moisture on your floorboards, let the shop know right away. While my issue was just the glow plug, sometimes these symptoms can also indicate a coolant leak developing in the heater core area. €440 was my total cost, but prices can vary based on labor rates. The part itself wasn't too expensive, it was mostly labor since they had to access some tricky spots in the heating system.

Thanks for that detailed info! Just scheduled an appointment for next week to get it checked out. You're right about catching it early, don't want a small issue with the auxiliary heater turning into something major with other heating system parts. Good tip about watching for coolant smells and moisture. Just checked my floors and everything's dry, no sweet smell, so that's a relief. The ventilation system is still pushing air fine, which makes me even more confident it's probably that glow plug issue you mentioned. €440 isn't too bad considering what could go wrong with the heating system. Just glad it's not the heater core, heard those repairs can run way higher. Will make sure to have them specifically check the glow plug and control module like you suggested. Really appreciate you breaking down your experience with such similar symptoms. Will post an update once I get it fixed in case anyone else runs into the same auxiliary heater problems with these models.