Hi

Please help. I have a 1996 Jeep Grand Cherokee with the heater A/C system where you dial the desired temp and it will heat / cool accordingly. When I turned it on this morning (with engine running) there was no fan and the digital heat display was black. Have checked all the fuses. Any Ideas?

Thanks in advance

Here is a pretty complete post on testing the ATC. You'll need to test for voltage and ground to ensure you have juice to the unit. Once you know you have that, this should help you out...

http://www.jeepforum.com/forum/archive/index.php/t-205487.html

Steve,

Thanks for the info, much appreciated. Just quick question do you know if the metal case needs to be grounded and do you also know which pin is the power?
I pulled the unit out the car but re-connected it to carry out the self tests. Unfotrunatly my display stays blank so either I not getting power to the unit or its the unit that is dead.

Robbie

I can't guarantee they are the same, but on my '98 diagram, the main power feed for the ATC controller is white/red and is pin C13 (latch side, 3rd from the end). You'll also want to check for switched power (ign on) on C12 which is Dark Green/Pink. Ground should be taken care of by D7 which is Pink.