Re: A/C problem update

[LEMONHEAD <br00206@binghamton.edu>]

Scott wrote:

<<
gas pedal) with the exception of one - I do not know where the switch that
senses engine overheat and cuts out the compressor.  Possibly, does this
info come from an existing sensor in another system? I know my temp sender
is screwed (dead gauge)......
>>

You are refering to the infamous multi-function sensor, which sends info to
the temp guage, overheat warning light, and cuts out A/C compressor if an
overheat occurs.  If your temp guage is not working, more than likely the
multi-function sensor is the culprit.  If this sensor is not working, then
it could NOT cut out the compressor.  I think you might be barking up the
wrong tree on this one...

Unplug the harness connector for the sensor and see what happens.

<<
Although my freon is a bit low, I dont think it is the cause of my problem
(as some of you have suggested) since jumpering the low pressure switch
doesn't cause the compressor to engage.  Once the compressor decides to
engage the air does get cold, just not REAL cold.  Also once it does
engage, it either cuts in and out erratically, or runs continuously. 
Sometimes it cuts in and out and then runs continuously.  It seems to have
a mind of its own.
>>

How did you "jumper" this switch?  If the system is just SLIGHTLY low on
freon, the compressor WILL cycle on and off.  I've had this happen to me
even following a RECHARGE; the tech did not FULLY recharge the system.  This
A/C system is very sensitive to freon levels...

<<
The strange thing is that is seems to operate normally after the car has
been running for a long time.  (i.e the compressor runs constant because
the freon is a bit low).  This is why I dont think that the condenser
thermostat is bad, because the condenser is coldest when the car has been
running for a long time and the whole system is no longer acting weird.
>>

This is easily explained by the fact that after a period of operation,
pressure builds in the system; once the heat pulled out of the cabin is
added to the system, the freon expands.  Thus, the compressor will cycle
less (i.e. the low pressure switch will not cut it out as frequently) and
more heat can be removed from the interior of the cabin.

I suspect your problem could be solved by recharging the system.  If you
have lost freon, however, there is a leak somewhere in the system.

Good luck!

Chris
1988 90