You can change the pressure switch yourself because there is a Schrader
valve under the switch that prevents loss of R12 when it is unscrewed. A GM
switch will outlast the aftermarket junk. Make sure you lube the o-ring on
the new switch with a little oil before you screw it in. If you have a
friend that knows electronics, have him install a "flyback diode" in
parallel with the compressor clutch coil. A 3A, 600V (or a similar rating)
rectifier diode from Radio Shack, etc. will do the job. Then your new switch
will last forever since it will no longer have an arc drawn at the contacts
everytime they open. The arc eventually burns up the contacts, causing the
switch to fail prematurely. When you jiggle the connection, you are actually
causing enough vibration to make the burned contacts connect temporarily.
Sometime in the late '90's GM started putting in flyback diodes, as my '99
Silverado has one.
Then your a MORON. 1994 was the change over year. I have a 94 S-Series
Blazer sitting in the front yard IT HAS R-12 from the factory. The 94 S
Pickups were either one depending on what part of the year they were built.
Also have a 94 GEO that is R-12 as well. Maybe you better go back to school.
And I know of two other 94 vehicles one is a Ford and the other is a
Chrysler They are R12 also
http://www.aircondition.com/wwwboard/alternative/current/7782.html Read the
Pacifism - The theory that if they'd fed
Jeffrey Dahmer enough human flesh,
Fine, I'll take a pic of my compressor when I get the chance and post
a link to it. How can I prove what year my truck is, even though I
know it's a 94. I don't wanna give away more info than I have to...
Come take a look at my truck. I INVITE you to. You'll see a nice
yellow sticker on the compressor (a Harrison if it matters, OEM I
believe) that states it's an R-12 compressor. No labels anywhere else
and you are afraid to use your name when you post an article, You
remind me of the fellah who showed up at a cock fight with a duck.
Besides the others don't have to prove squat to you, If you think they
are wrong then it is up to you to prove it. Until then they are right.
Before you replace the pressure switch, check the metripak connector pins. These
have a tendency to lose there spring as they age in an elevated temperature
environment. You can re
bend the spring clip to repair it or replace it all-together.
Not the $250 for the conversion, which they said they'd have to do so
they could re-charge the system to test it.
This shop is good to me, all my really major repairs go to them and
they haven't done me wrong yet.
The label that states the refrigerant type and charge.
But you stated that you get cold air when you jumper the low-pressure
switch. That would indicate that there is at least enough refrigerant
in the system to allow testing. Which tends to support my contention
that the shop in question is not qualified to do A/C work.
*Somewhere* under the hood is a refrigerant identification label that
will state the type of refrigerant used, and the amount necessary to
charge the system. Most are on the evaperator case, but all are near
the service fittings.
Then, either they are not competent to service A/C, or, they threw a
number at you to keep you from asking for free work.
OK, I take that back, there IS a label, it's just facing the fender.
Makes it hard to read without a small mirror, or removing the fender.
Makes no diff. anyway, I fiddled a little with the switch/contacts in
question and it now blows cold again...
You dont have to open the system to replace the switch! It just unscrews and
there is a shrader valve that holds in the pressure, just like on your
It is probably just a bad connection at the switch anyway. If you move
the connector and it kicks in it is most likely just the female spade
terminals inside the connector that are loose. get some needle nose plyers
and squeese the spades a little and try it again. If you have to you can get
some spade connectors and replace the connector altogether. just cut it off
and put on two female spades on the two wires and hook it back up to the low
pressure switch. It doesnt matter which wire goes where. No big deal.
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