My 84 has been having problems with the heater blower motor not turning on all the time. I noticed that the A/C compressor also turns off when the blower does too.

Im getting tired of searching for bumps in the road to get my blower and A/C to turn on.

I think it's somewhere in the HVAC control unit. Suggestions on how to diagnose?

 

Check the AC Relay, then start looking at plugs to see if you have bad connection, bad grounding or bad plugs all together..Usually if something is cutting in and out and a bump will help resolve it then that bump is jaring something and leads me to think bad or lose wiring and/or grounding.

 

X2 on what OKC says. The grounds in Cherokees are notorious for being the weak point in several areas.

 

Yeah. I will take the bezel off tonight and start jiggling wires I guess and locate the culprit. Figure it's better to do it now than in 2 months with the snow is flying and I don't have any heat!

Fun fun.