I have had the issue of my fan running constantly even without the key on. So I searched online and thru this forum I found out the ECM was bad. Well i didn't have an extra $350+ laying around, so i decided to open it up and see what i could find. Long story short i found a bad diode replaced it and problem was solved! The diode is a 50 cent part! Not sure if this will fix everyone's but i just wanted to show what i found. Here is the link to the diodes that i bought: SMCJ22A-E3/57T Vishay Semiconductor Diodes Division | Circuit Protection | DigiKey

Machine: 2009 Trailblazer 330
Issue: Fan runs constantly (NEVER turns off)
After engine starts the Hot light comes on
Issues started after jumpstarting the quad from a car

 

Good deal..Glad you found a solution to the fan and hot light circuit.They cram way too many functions in this one box. Along with what you repaired there's a battery protection circuit,lights relay,accessory power, starter circuit and charging circuit. If you could keep on exploring on the other functions the electrically inclined owner can repair different parts of the module that fail rather than paying big bucks on this thing.

 

How did you come up with this part # ? The link you have is for a zener diode .

 

Believe it or not I just Googled the text on top of the diode and after a little searching i found it. Just little background on my self i built PCB's for over 12 years for avionics.