Air Conditioning (A/C) Trouble

Hello,

I'm really hoping that someone out there can help me find a solution to
this problem that I'm having with the A/C in my Jeep. I recently
purchased this Jeep, so I don't know much about its service history.

The problem is that the A/C compressor only kicks on when the control
is set to 'defrost' mode. In any other mode, the A/C will not come on.
I took the Jeep down to a local quick lube shop to have the system
evacuated and recharged, hoping that low refrigerant might have been
part of the problem. This, however, has done nothing to solve the
problem. The guy told me that he pulled out just over 16oz. of
refrigerant and the total capacity is 24oz. so, it was a little low.
It might just be placebo, but the air does feel cooler. It is
diffifult to feel that cold air on these hot days, however, when it is
coming out on top of the dash.

Any help or suggestions will be greatly appreciated.

 

....by the way, this is a 1999 Jeep Grand Cherokee

 

3020i don't know about your state but in mine a quick oil change place
cannot do a/c work
the system needs to be tested correctly with dye or a sniffer you have a
leak for sure

 

Excuse me, but DUH!! If the A/C worked in ANY mode, then its not a
problem with the refrigerant system. Its a problem with the CONTROL
system- possibly the mode selector switch (assuming this vehicle doesn't
have an automatic climate control system).



The guy told me that he pulled out just over 16oz. of

Which absolutely did NOT warrant an evacuation and complete recharge.
These stupid quick-lube places should be run out of buisness- the amount
of damage they do to otherwise healthy vehicles is appalling. If they
don't know the proper procedures to place guages and thermometers on
the system to determine the state of charge, and then know how to simly
ADD refrigerant instead of wasting your money by doing an evac and
recharge, then they shouldn't be touching an A/C system!

 

You don't know if the service guy did put a thermometor on the system.
He might have done so, or he might have put a quick-readout guage on
the system and seen it was low.

In theory they should be able to pull all the refrigerant out of the system
with a machine, then put the same refrigerant all back in plus what
additional
was needed to get the system to the proper refrigerant level, in probably
the same time as adding refrigerant. I don't know if
the usual practice at these places is to just dump the refrigerant to the
bottle
that goes to the refinery, though.

However, to be perfectly frank, if they are reusing the customers's
refrigerant
in his own vehicle, then that is a much better system than using
thermometers
and such. With the thermometers your only getting a close approximation of
the system capacity, not the exact amount. Even at a good A/C place it is
unlikely your going to get the master A/C mechanic to be doing a simple
topping off of a low system, instead your going to be given the entry level
boob
who may or may not be any good. I'd rather have him working off very
simple diagnostic instructions (look at that guage, turn it off when the
guage
says 24 ounces have gone in) than complex ones.

Also, to be frank, checking the A/C system state of charge should be SOP
at any A/C repair place. Not because it has anything to do with the
problem, but
because it is very quick and easy to do, and if the tech discovers a leaking
system,
then he should sweep the system for leaks. This is a
good-for-the-environment
sort of thing that helps all of us.

Ted

 

wrote in

Oddly enough, I think I have the same (or a similar) problem. I had a
mechanic friend "recharge" my system. However, when he evac'ed the
system, he took out as much R134 as he put back in and then added the
dye just in case there was a leak. I haven't tried the defrost trick
yet, but while sitting at idle before driving off, it cools just fine.
However when I drive off, at low speed or high, the compressor kicks
off and stays off. It's driving me crazy.

Vince