no AC/compressor does not turn

92 twin cam, 5 speed, 119 k miles, 4 door.

AC compressor does not turn/engage when AC button is pressed in (thus,
no cold AC air!)

when button is pressed in, light comes on. Cooling fan does not switch
on automatically as it should, but does operate when the temp. sensor
needle reaches the 3/4 mark. Re-circulation button and blower fan also
work (all speeds)

Checked the fuses & relays in box next to battery and in panel near
front passenger side footwell - all OK. Checked to make sure electrical
connections at compressor & fan are OK. AC was fine a couple of weeks
ago.

Is there another in-line fuse somewhere that I am missing (GM ACs use to
have a kind of thermo fuse attached to many of their older compressors
in the 70s & 80s) or something else? Any pointers would be greatly
appreciated!

Thanks.


=================================

" ..... I ain't no bandleader!!"

 

You have lost some or all of the Freon charge, enough to turn off the
pressure switch. 92's had R-12 I believe, which is hard to find and
expensive. You probably have to convert to R-134a after you find and
fix the leak(s).

 

Your freon charge is low enough that the low-side pressure switch opened. My
'92 did this last month for the first time ever. That switch is so the pressure
will not get too low to damage the compressor, or freeze up the system.

I found my leak at the front compressor seal. I immediately converted the
system over to 134a along with some leak detector and sealer. So far not a leak
to be found... time will tell. I still get 40 degree air at my vents just as I
did with R12.

James

 

Thanks for the quick replies. Is converting to R134a a do it yourself
job? I thought I saw kits for converting at Pep Boys a while ago.

Also, if the compressor does not turn, how would the new stuff be drawn
into the system? Is the pressure released from the opened can
sufficient to get the refrig. into the system, which will then
close/re-set the valve in question? Or is there some dealer-only kind
of tool/device that's needed?

Thanks again!


=================================

" ..... I ain't no bandleader!!"

 

Checked out some of the R12 to R134a kits today. Is the fill for R134a
to R12 a 1:1 ratio? eg: the compressor says use 2.25 lbs of R12 (36
ozs), is that how much R134a I should use? How about oil fill, in
ounces (can't find the amount needed in the chilton & haynes books).

Kits say have existing R12 removed by a qualified service dept - any
ideas on how much that would cost?

thanks again!


=================================

" ..... I ain't no bandleader!!"

 

I have heard all kind of ratios for R12 to 134a.(70 to 90%) I personally put in
3 oz of PEG oil and 35oz of 134a. My can that contained the oil/dye/sealer only
contained 11 oz of freon - that is why the odd number of total freon ounces. So
far the system has performed perfect!

James

PS - I went to the trouble of removing my compressor to remove any remaining
oil. It was a waste of time. The local Saturn dealer claims you don't have to
drain it anyway. But they also told me to add 5 oz of PEG oil, but I thought
that was a bit much so I settled for 3 oz.