Caddy Maxi 1.6 heater blower not working

[120COZ]

Wed Apr 19, 2023 12:37 pm

Caddy 2012 1.6 heater blower not working small write-up:

1. Check the blower motor to see if it actually spins, if it does keep reading, if it doesn't...do'h, change the motor
2. Check the green resistor pack and see if it works (it should only on speed 4 if it's a bad one) if it works on all speeds keep reading
3. See if you the wires from the green resistor pack to the central console have continuity, if they do, you're good, keep reading
4. Check the fuses (33 under steering wheel) if it's good, keep reading
5. Take the panel under the steering wheel out, on top of the fuse box there is a relay box
6. Check relay 644. If it's good keep reading
7. No the tricky part come into play:
- bridge the 2 BIG prongs of the relay (blower works?)
- check the thin wires from the relay (broun and grey/red stripe)
- brown thin wire at the back is ground, thin grey/red goes to BCM
- measure voltage, there should be 12V on those small wires. If it just gives you a jolt and then nothing... There's the problem. Either bad ground or bad positive (my issue was the positive not getting constant V and the relay opened)
- take positive from battery and stick it in the back with the grey/red. Works? Bad positive. Doesn't work? Keep reading
- take negative from the body and stick it with the brown. Works? Bad ground. Doesn't? Keep reading
- Doc suggested to disconnect the battery for a hard reset of the BCM and it may fix the issue.

If you're unlucky enough and nothing works it may well start praying and finding quotes from a professional because here is where my problem was fixed and I haven't dug further. Good luck!

Thanks @Doc and @petrev for their knowledge which helped me isolate my issue. I hope this write-up helpes someone!

Very good steps to follow and recommended by our colleagues