[Shotimes] High-Pressure cut-out switch questions..

[Steve Weinrich]

The switch mounts to a self-contained Schraeder-type valve.  You can replace
it without disturbing the charge in the system.  As  a precaution in case
the valve has failed, wear hand and eye protection.

R134a systems have the high pressure cutout switch as a safety device in the
event of AC system overpressure.  Somewhere around 450 psi, the dual action
switch engages.  One set of contacts opens, removing power from the clutch
coil.  The other closes, forcing the fan to high speed.

It sounds like you have correctly identified the fault as a shorted switch.

The site you referred to is probably Nook's.  It is at
http://www.utahfordclub.com/rac.htm  His problem did not include yours, but
the page is worth bookmarking for future reference.

Steve W

----- Original Message -----
From: "Jeremy" <jeremy@carrieandjeremy.com>
To: <shotimes@autox.team.net>
Sent: Wednesday, August 11, 2004 11:40 PM
Subject: [Shotimes] High-Pressure cut-out switch questions..


> Well I finally found out what was keeping my fan's on all the time and
> giving me the 539 code. I chased that pink/light blue wire all over that
> engine bay and finally ended up at the high-pressure switch at the front
of
> the car. I belive that's what this thing is anyway.
>
> If I remove the connector from it, the fans will eventually switch to low
> speed and then shut off. But as soon as I plug it back in, the fans kick
> right back on. (This is with ETAC to OFF).
>
> Now I understand this switch is supposed to cut the A/C system and keep
the
> fans on when the pressure is too high (??). But seeing as the system
itself
> is off, I'm guessing this switch is shorted internally or something.
>
> Do I have to have the system evacuated to replace this switch? There was a
> realllly nice webpage someone did that went through a whole host of
> diagnosis for the A/C system but I can't find it right now.
>
> TIA,
>
> Jeremy
>
> '94 Opal ATX 116k
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