AC and Recirc Controls

[acidfire52]

OK guys here is an odd one. If I disconnect my battery, after I hook it back up, my A/C and recirculation buttons work fine. Can push them, light comes on, all is good. But, only for about a day. Then, nothing. The top button, rear defroster, works fine.

Is there a computer that controlls these?

Any ideas? Am really going to want those buttons come summer.

[DaveVoorhis]

You're probably low on refrigerant.

[acidfire52]

I think I am, but I don't see how that would keep the buttons from working...

After a day the buttons just don't work anymore. No lights.

[DaveVoorhis]

There's a static pressure sensor in the system. When the battery is disconnected, the A/C controller resets and re-samples the pressure. If the pressure is too low, off goes the lights and the A/C is inactive. It sounds like your pressure is right on the edge -- just enough to keep it running until it cools off at night or something, and then it triggers the pressure sensor.

[Montreal525]

Yes but it shouldn't affect the recirculation switch. If all else fails, those are signs of a declining ventilation control module, IHKR or IHKA... I had the same symptoms last fall and got a used one for $40 from Vines auto on Ebay... Problem solved since then... And it's a 5 minutes swap...

Jeff

[acidfire52]

IHKR or IHKA... ... How would I know which one I have? And where is it in the car?

Thanks

[acidfire52]

Nevermind.. Looks like the IHKR is the manual system I have. Will look into getting the system filled and see where that leaves me. Then, replace the computer if need be.

Could still use info on where this sucker is.

[Montreal525]

All the way at the back of the center console, near the firewall... You remove the glove box and some trim and it's there... You just pull it out, unplug it, plug in the new one and re-insert...

Jeff

[DaveVoorhis]

Recirculation activates the A/C compressor.

IHKA is the fully-automatic system with buttons, horizontal temp and fan wheels, but no sliders.

IHKR is the semi-automatic system with temp and fan knobs and sliders.

The control module is behind the HVAC box, accessible from the right-hand side. You can see three cables going into it.

[Montreal525]

Recirculation activates the A/C compressor.

2 years ago, my a/c condenser was screwed and all the gas leaked out but recirc. would still engage... Then again, my car is not a reference to what works and what's not suppose to...

Jeff