Factory Auxiliary Heater Driving me Insane!

[buyingconstant7]

Back when my 2006 Jetta TDI was new, I specifically remember it delivering me near-instant heat and the idle raised to about 1,000rpm when I first fired it up on a cold day. Assumed it had some sort of heater in the airbox and left it at that, it was great! Fast forward to 15 years later, I noticed it wasn't giving me heat anymore right away, and I'd have to wait until my coolant temp started creeping up. I scanned it for faults and sure enough I have the code set in the aux heater module for heater element defective. I opened it up, and visually couldn't see any issues with the soldering. I went to a local scrap yard and pulled two from other 2006 Jetta TDI's. Tried one, code stayed and nothing happened. Tried the other, code went away instantly without me clearing it. Did an output test, nothing happened, then it set the same code yet again. I checked my original one, and I wiggled each resistor with a screw driver and one came off easily, the other ones wouldn't budge. So I assume I've found my problem. Just wondering if anyone could give me advice, I hear the car locks out the module once the aux heater has been detected as a failure, is this true? Can I just reolder and slap it in and everything will talk to each other and it's good again? And should I add solder to the circuit board where the resistor came off? Or should I just hold a hot solder gun to the resistor, allow the old solder to melt and let it cool again?

 

[buyingconstant7]

I'll answer my own thread since I did some experimenting. I re-soldered all 3 of my aux heaters just by having a friend hold each of the 5 small resistors down with a small screwdriver so they don't move, and then I heated them up for about 10 seconds each side of the resistor with a soldering gun. One of the aux heaters I messed up on and ruined a contact, but the other two went flawlessy. Now they both work great. So I will confirm for anyone wondering, the aux heater module does not lock itself out, it will set a permanent and non-erasable code if it sees it cannot properly hold and maintain a minimum of around 650 Watts and can't draw more than 70amps. Most times you can manually command a bad aux heater on through output testing it through VCDS/OBDeleven, but you'll notice the amps are well below 100, and the watts are well under 1000. After I resoldered mine, my values are very close to 1,000W and 100A. The code will immediately become intermittent and erasable code as soon as the car sees a good heater plugged in.