A/C Help - Chevy Venture - Where is Low pressure switch?

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Lee - 09 Jul 2007 13:33 GMT

Our A/C on our 2003 Chevrolet Venture van started blowing only warm
air. I checked the pressure and there is coolant in the system (I
checked pressure with a guage on one of those hoses you get with the
can of R134, didn't put any R134 in and it reads about 100 psi on a
85
degree day). The compressor is not coming on, fans are on. Fuses
are
ok. But I cannot find the low pressure switch. Does anyone know
where it is ont these vans?

I found one switch/sensor underneath the air box on the A/C line, but
this has 3 wires, I thought the low pressure switch had only 2 wires.

Any other thoughts on what it might be, common problems? Hoping its
not the compressor or compressor clutch.

Again, its a 2003 Chevy venture with rear Air.

Any help is greatly appreciated.

Thanks.

Lee

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Comboverfish - 09 Jul 2007 17:36 GMT

> Our A/C on our 2003 Chevrolet Venture van started blowing only warm
> air. I checked the pressure and there is coolant in the system (I
[quoted text clipped - 19 lines]
>
> Lee

You found the pressure sensor (not switch) that GM uses on their A/C
systems. It is a three wire transducer that has 5v reference, ground,
and a return signal wire to the PCM. The easiest way to check this
function of the system is to read A/C system pressure on a scan tool.
Any properly equipped shop would start this way, then go to component
diagnosis if the scan data showed a problem with the pressure sensor.

The PCM actually controls the compressor clutch on/of function. It
does get it's command to turn on from the HVAC module, which takes the
dash controls and evap temperature into consideration.

If you don't have access to a scan tool, you can first check the
compressor plug to see if voltage exists when A/C is commanded (engine
will need to be running, so perform this test carefully).

Toyota MDT in MO

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Ashton Crusher - 10 Jul 2007 04:45 GMT

>Our A/C on our 2003 Chevrolet Venture van started blowing only warm
>air. I checked the pressure and there is coolant in the system (I
[quoted text clipped - 11 lines]
>Any other thoughts on what it might be, common problems? Hoping its
>not the compressor or compressor clutch.

Hot wire the compressor to test it to see if the clutch and
compressor are working. If it comes on you can get a reading with
your gauge and see how low it's pulling.

>Again, its a 2003 Chevy venture with rear Air.
>
[quoted text clipped - 3 lines]
>
>Lee

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