98 GC AC Malfunctioning

unnecessarily

Well, you said the key word you turned it off and then back on and it cools. If it was a low charge or a compressor issue it would not cool. It is in you climate control switching and associated sensor and damper control. It is usually caused by a diaphragm failure of the air box. Which is located in your dash behind everything. Allow some times the switch gets dirt on the contacts and needs to be removed and cleaned with a good contact cleaner. You need to purchase a vacuum hand pump to test the diaphragms. Make sure the hoses are tight and draw about 5hg if the needle drops the diaphragm is bad replace it also, there usually 1 or more under the dash test them all. It is not a hard job just time consuming usually an 8 hour labor charge at the local dealer hence the high cost.

It might be worth while pulling any diag codes from the system that might quickly point out busted components.

For a simple test, turn the thing all the way down to the coldest temp and then open the doors and run it for about 10 minutes. You should be getting somewhere near 40 degrees at the vent next to the controls.

Problems with the auto A/C can range from simple loss of charge to simple stuff like the internal temp sensor [or the fan that drives it] being messed up.

...and can cost as much to fix as an engine repair.

I don't believe there is a single diaphram in the GC air conditioning system. It uses servo motors driven by the auto temp control system.

The evaporator is prone to leakage, as is one of the A/C lines that passes just in front of the battery mount.

With the thing on full chill, fan on high, doors open, if the clutch cycles frequently at 70-80 degrees ambient, most likely cause is low charge.

To check the controls, use the Temp rotary and the A/C and Recirc buttons. [caution, from a 95 Factory Manual...]

Push [ A/C ] and [ RECIRC ] and hold while rotating the temp dial clockwise one click. All segments should light up.

Let go of the buttons and you should see "00".

Read Diags by pushing EITHER the [A/C] or [RECIRC] but not both.

You should see a stick figure at this point. If the display stays at "00" there are no fault codes.

If you see 25 or 29, the Auto Temp Control Module is tweaked.

If you see numbers, record them all and in the sequence they appear and post them for someone with a 98 FSM to decode for you.

Thanks to everybody for the advice. I did follow instructions to read Diagnostic Codes and all I get is 00....no numbers. Also, tried running for

10 minutes on lowest cool setting/high fan and the air I'm getting from the dash vents is cool, not cold, but nowhere even close to 40 degrees. So, if there are any people here with AC experience, I'd appreciate your input.

Thanks for all your help! BEK

Have the system checked for leaks and charge checked.

You might want to take a look at the evaporator, some ZJ's had problem with them corroding. Also look at the A/C pipe along the battery for corrosion. Common source of leaks.

Thanks for your help Lon. Does the fact that I didn't find any error codes mean that there are no major parts gone bad....like the compressor or Control Module? Is the evaporator an expensive part? Trying to get a little education here before taking it in.

BEK

No codes *may* be good news... Dunno how much the evaporator costs,

but it may require a few other parts replaced at the same time. Take a look at it for any rusted, corroded appearance. Looks like a tall metal cylinder about halfway between the radiator and the firewall. If you live in an area with a lot of competition, an A/C specialty shop should be willing to pull a quick pressure and leak test, plus a new charge for lots less than the dealers usually charge.

Thanks again for all your great advice, Lon and all. Guess we'll find out next week!

BEK

For anyone who is interested....

Took our 5.9 into the shop yesterday and they determined that the problem was the "air conditioning and cooling fan module". Working great now but spendy at $670. Sure wish my husband and I knew how to do this stuff ourselves!!!

Thanks again for all the help, BEK