EATC malfunctioning, cannot get into diag mode

[shadowless127]

My EATC has been acting up since Saturday afternoon. It started when I stopped for gas. Turn the engine back on, only fan speed that worked was Hi, and temp on Max A/C was stuck on 60 regardless of what I set it to. Got to my friends house, turned the car off for 10 seconds, turn back on, now all fan speeds worked but the A/C wasn't kicking on when in Max A/C mode. Turned off, let sit for few hours. Get in to leave and everything is functioning normal. Yesterday everything worked fine. Today went I went to leave for lunch, it wouldnt kick on any fan setting except high. I tried to enter Diagnostic mode (Off and floor at the same time, then hit automatic within 2 seconds) but it doesn't respond to that command.

Am I safe to go to my local JY and pick up a new unit and plop it in?

 

[albi1cnobi1]

Does sound like the control unit is crapping out. You didn't say what year you have, that does make a difference. Try to match the year because there are differences. 95 thru 97 are the same, and 98 thru 01 are the same and differ from the earlier ones. Hope that helps.

Sorry just saw your sig. You would need the 98 to 01 model.

 

[shadowless127]

Does sound like the control unit is crapping out. You didn't say what year you have, that does make a difference. Try to match the year because there are differences. 95 thru 97 are the same, and 98 thru 01 are the same and differ from the earlier ones. Hope that helps.

Sorry just saw your sig. You would need the 98 to 01 model.

Yeah, I usually follow the 98+ rule because it seems most parts follow that rule.

I got it into Diag mode but it doesn't show any codes, and now it's stuck on heat instead of AC. Thankfully my dad is out of the country till the 1st so I have his 09 CTS4 at my disposal until I solve this.