i vac'd the empty system to -30, put in 2.5 cans freeze 12 with
engine running and pump hotwired. compressor wont run w/o hotwire.
tried jumpering pressure switch first. switched 3 different dash
button/wheel control assemblys, still wont run w/o hot wire. at idle,
i had 38 on low side, 170 on high, 80 degree outside air, car always
runs at 80 centigrade. aux fan works automatically. at idle cabin
temp cxame down to 60 degrees. at 1200 rpm low 30/high 190 then temp
came down to 50 degrees. still try plugging back in pressure switch
wire and no compressor. at 2800 rpm 60low/90 high temp in cabin still
50 degrees. after turning eng off low side 80/high100. i can see
flow like crazy in the sight glass, although can't say it looks like
bubbles. i bought this car as is so don't have a history. if i got
the compressor to run on its own be a big start... thanks for any
Sounds like you don't have enough R-12 in the system if you can still see
bubbles in the sight glass. A full system normally gives no indication of
bubbles, thus you can't see anything moving in the sight glass. However, 38
psi on low side should certainly be enough to at least operate the system. I
like to hold the can while viewing the sight glass and stop adding coolant
when the bubbles stop. This may well get you more than 38 psi on the low
side but that's usually okay anyway.
You said you hot wire jumped the pressure switch. Is this actually what you
did rather than put a jumper between the two connections on the pressure
switch plug? This is a two-prong switch connector which you should hot-wire
first rather than the compressor anyway. Hot wiring the pressure switch
itself does nothing.
I'm guessing the problem is the pressure switch if the compressor runs when
you jumper the switch plug. Problem is you normally have to take the switch
out to check or replace it. There is a way to check the circuit if you have
another switch laying around and an air compressor. Take the uninstalled
switch, plug the connector onto the two terminals, start your car and turn
the AC unit on. Take an air nozzle with a rubber tip and press it tightly
against the air orifice on the bottom of the switch where it screws into the
drier. If the compressor comes on when you apply air pressure your existing
switch is bad. If it doesn't, and you are sure you're getting pressure to
the switch, then the problem is somewhere else in the system.
If that is the case your dash control may well be the source although you
say the fan works properly.
How much R-12 did you say you had? Changing the pressure switch means
draining the entire system and starting over.
To all you environmentalist kooks, please don't tire me with those claims
about that alleged hole in the ozone caused by cfc, etc. That's a proven
cyclic event that takes place every 50 years or so.
Good luck Gary.
thanks for your reply, i'll try your t/s suggestions. what i meant by
jumpering the switch was like pulling the leads a bit but not
disconnecting them. then then take like a dime or something and touch
both posts. same as jumping the leads right? still no compressor run.
only when a hot lead from batt to dual wire lead makes comp run.
here's my question. is it basically the dash controls and the pressure
switch that control the compressor? are there other things in the
circut i can check. i appreciate your help, want to travel to south
dakota to see my brother early july.... -gary
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