jcman

...and I know you don't want to hear this I would check the screen on the orifice tube, other than a trash jammed condenser "that I doubt" it's the only other place.

divil

I hear ya...I will check it if I don't find anything up with the fan(s). The condenser is brand new so I would be very surprised if it could have jammed up that quickly.

How critical is the positioning of the orifice tube? I noticed that the old one was just pushed in there and I didn't see any system for locating it precisely, so I put the new one in to what seemed like the same location. Maybe I caused a blockage somehow.

jcman

But I think you will find your answer when you pull it out.

divil

ok just checked the electric fan. I definitely only have 1 electric fan, and it's not switching on when I turn on the AC. Should it the fan come on right away when the compressor clutch engages? I didn't want to wait and see if it comes on eventually because I was afraid the high pressure would damage something. But I ran it for 20 seconds or so (when I had the gauge hooked up the pressure wasn't building up that fast). The electric fan didn't move. Could that be the problem?

2.7Lturbo

yes, the fan should come on when the ac compressor is engaged. this prevents the high side from building up

divil

Cool, that is something I did not realize about AC. I am confident I can find and fix the reason the fan is not coming on.

Incidentally, at what pressure does the pressure switch cut the compressor? I was surprised when I saw mine soar over 300 psi without the compressor cycling off. Presumably the switch won't allow it to get dangerously high?

divil

Tested the fan, it doesn't work when wired directly to the battery.

I also tested the voltage at the other side of the connector, and it switches on when a/c is turned on, then it goes off when the a/c is turned off and the high side pressure drops below about 200. So it seems everything is working correctly except the electric fan motor itself.

I removed the fan unit, and I have continuity from the connector to where the wires are soldered inside the back of the motor housing.

Is there anything that can be done to fix the fan motor? It spins freely by hand so it's not seized.

jcman

That fan must run in AC mode to reject the heat off the condenser coil and it sounds like this issue may of caused the demise of the first compressor.

If you are sure that 12volts is at the fan motor and nothing is happening its most obvious the motor is bad and needs to be replaced.

2.7Lturbo

not only is it the demise of the first compressor, the high pressure cut off switch might also be bad.

divil

Yeah I was thinking this might be what killed the old one...it was completely seized!

Anyway I was reluctant to test let it get high enough to test the high pressure cut off in case I damage anything. I asked on an a/c forum and was told that the switch has 3 modes:

-low pressure cut off: 30 psi
-fan on: 223 psi
-high pressure cut off: 441 psi

The low pressure cut off and fan control seem to be working but only approximately. The power came to the fan connector before the high side pressure reached 200. When I switched off the a/c, the fan voltage stayed on until the pressure dropped below 200, then it switched off. I wasn't sure if that level of inaccuracy is acceptable, but then I am not sure where the poster who told me thoe threshold values that got his info from.