97 SHO A/C Questions

[aarmel732]

Hey, small problem with a car the PO said was "mechanically perfect". The A/C does not work at all. We hooked up a can of referigerant to the low side and the gauge went all the way around to the stop. The A/C shop says it is a wiring problem. The fuse is ok. The compressor does not even kick on at all. Could this be a football, compressor pressure switches, or just plane overcharged? Where do I start? Thank you guys so much, you guys are the masters at this. I am looking forward to my SHO ownership, but it sure is hot right now! Also, is it possible to remove the automatic climate control and convert to the radial dials?

 

[medgraphsho]

I think your supposed to hook it up to the high side???

 

[aarmel732]

Tried, adapter does not fit the high side. Unless I am calling them the wrong things, low back by firewall, high up front near compressor.

 

[Silvapain]

Charging is done on the low side.

Did you check the low and high pressure switches?

 

[aarmel732]

No, how is this done?

 

[naval-avi8or]

Did you check for 12 volts at the AC clutch. Could just be a airgap out of spec.

 

[aarmel732]

Clutch is not even trying to engage, would the shim issue cause that kind of a fault?

 

[naval-avi8or]

Clutch is not even trying to engage, would the shim issue cause that kind of a fault?

YES!! If the airgap is to large the AC clutch coil can energize and not have enough electromagnetic force to pull the face plate in and engage the compressor.

 

[Silvapain]

Do the "broomstick test":
http://www.v8sho.com/SHO/AirConditioningCutsOut.htm

That will tell you if the clutch needs to be regapped. The procedure for regapping the clutch is also outlined on V8sho.com

 

[nothingtoseehere]

Make sure your gauge is reading correctly. Some need to be "held" tighter on the connection to ensure a proper reading, also you want a reading with the A/C on max and the clutch on the compressor engaged.

To check the switch, disconnect it from the evaporator, take the connector and jump it with a paper clip. If the clutch engages with the switch jumped and a/c on max, then your pressure is too low. If not, reconnect the switch and do the broomstick (persuade the clutch to engage with a broom handle). If ti engages and holds for a few seconds, then you likely need to de-shim the compressor.

Lower the sub frame a little, remove clutch, remove shim, re-assemble. It is a VERY easy job.

Essentially here is what you are looking at for possible causes:

Charge either to low or WAY to high (checked with a/c on max and clutch engaged - if too high, evacuate some, if too low, add some)
Pressure switch dead (if the pressure is correct, the air gap is correct and you still cant jump with a paper clip, time for a new switch)
Shim-ectomy needed. (switch is good, pressure is good)