OK -- here is the long and the short of it ....

Hard-wiring does cause the clutch to engage, and the compressor to spin (a bit grudgingly from what you write - but it does spin). The clutch works, so it is not the problem. Next step is to figure out why the voltage is not getting there the "normal" manner. In the control circuit, is what is called a "trinary" switch, which does several things:

1) Stops the compressor if the low side (suction) pressure is too low
2) Stops the compressor if the high side (discharge) pressure is too high
3) Permits the compressor to operate between those high and low limits
4) Turns on the radiator fan when the A/C is commanded ON

You need to get someone with a complete set of gauges to look at the system, and get the readings for both suction and discharge side when the engine is off, and also when the engine is running, and you do your jumper thing on the compressor (force it to run with the jumper wire). That should give us the next direction to go

 

Thanks for the speedy response, OA.

I'll get the gauges and post the low and high side readings (as did snellenj) on, off, and with compressor jumpered.

(Also, I noticed while filling the low side with refrigerant that the port now seems to ever so slightly leak refrigerant when the filling adapter is removed-- the only thing keeping the pressure temporarily high enough to test things is the cap for the port....makes this all that much more fun) I fear the low side line will need to be replaced since the fitting appears integral to the line.....yay......

By the way, where are these high/low pressure switches located?
I assume they are somewhere else in the A/C line paths? They don't seem to be near the compressor...

Really need a 95 wiring diagram to avoid asking these trite questions......

 

To answer your question, the trinary switch is located in the high pressure (discharge) portion of the A/C loop. For example, if you look at a 2002 DOHC L200, you will find the trinary switch located on the passenger's side of the vehicle, just behind the headlight, mounted on the A/C discharge pressure line, very close to where you would hook up the gauge to measure the high pressure of the system.

Now -- on my '93SW2 DOHC, the routing is like totally different, and the trinary switch is located on the driver's side of the car, tucked between the battery box, and the driver's side strut pillar mount. Remember, that we are talking about high pressures here (sometimes as high as 275 pounds per square inch), DO NOT TRY TO REMOVE THIS SWITCH UNLESS YOU ARE TOTALLY SURE THERE IS NO PRESSURE IN THE A/C LINES (gauges read zero, zero, ZERO) I don't wanna come over there and have to pry that switch out of your skull .....

 

ok so I had the opposite problem...when I jumpered it nothing happened...so that means my compressor/clutch is bad correct? So is that what I should replace now? Thanks Ocean!

Ok Derf if you live close by I can let you use my gauges, I live in Greencastle IN, just let me know if you need some...ok bro!

 

Ayup -- best guess is the compressor clutch is shot/frozen. Expensive, I know, because you can't buy a replacement clutch (as far as I know - you got to get the entire clutch and compressor assembly) Sorry to be the bearer of the bad news .....

 

No prob bro, I will go to pick-a-part in Indianapolis and get it...they warranty it for 45 days, and it will only cost about $37. So it really isn't that bad...Thank you very much! If I have any more problems afterwards I shall write on here again

 

That's the switch? Someone asked a question about what that "sensor" was in a different post last week--and was planning on replacing it--- I suggest we find that post ASAP and pass along your warning before someone gets hurt.

I will check the wiring and connection to it -- might be corroded. So that's where the high pressure switch is. I promise not to f with it in a dangerous manner. Thank you for the sincere warning, as I have not done A/C work before (clearly).

So both the low and high pressure switch are located inside the portion that sits inside the line, yes? Which means if I check and find an open circuit then one of them is open since they are in series......

Out to the store for the gauges.

Thanks again, OA!
__________
Snellenj -- I live in NJ-- but thanks for the offer, dude! (People with Saturns are just cool)

 

Actually -- the switch will read OPEN under the following conditions:

1) Pressure below low setpoint (no freon condition)
2) Pressure above high setpoint (excessive pressure)

If it is a true trinary switch, there will be three wires going to the switch. That portion of the switch closes (to run the condenser fan) when the pressure is high (but not excessive)

 

Only two wires going to the switch in that line.

Got the gauge manifold set but going to dinner with the wifey -- will measure later...

Did have time to investigate pressure switch. Switch reads open with 20 PSI (makes sense), but also still reads open with 50 psi low side pressure (doesn't seem to make sense). I had a sloooowwwww leak in the system and I have not added even a full can of R134a since I started posting, but the switch refuses to close (except that one time for the three minutes the A/C clutch engaged). I can't conceive that the system is overcharged, so I'm thinking switch may be bad in addition to other issues yet to be determined....

stay tuned

 

"Normal" stable state (sysem off) pressure in a R134a system is about 70psi both high and low gauges. When it is running properly, the low side will be about 40psi and the high side will be about 240psi. Oh, and the air out of the unit will be cold .....