SII air conditioning problem

[jawsplace]

My AC works fine but I had a freon leak that I finally located yesterday. I fixed where it was leaking at a compression fitting, charged the system, all seems fine. However the AC is now doing something that I can't figure out. There are the two knobs to control the AC's fan speed and amount of cooling. The compressor clutch will only click on when the fan speed is below about the mid point. When I turn the fan speed knob higher than the mid point the clutch disengages. Turn it back down below the middle speed and the clutch engages again. The cooling control appears to work as intended and the compressor cycles engagement depending on how min or max the cooling is set at. But I can't turn the fan speed up any higher than mid way otherwise the clutch clicks off. I can't figure out this one. Any help for me?

[fredsterra]

The fan switch sends power to the thermostat control. And when the switch gets worn it can create an open circut to the temp. control switch. You can replace the fan control switch. Or install a (AC On switch) around the fan switch.

You can most any toggle switch or a push button switch. All your doing is sending power to the temp. control switch. That sends power to the thermostat to the comp. clutch.

DO NOT WIRE THE SWITCH DIRECT TO THE COMP. CLUTCH. THEN YOU WON'T HAVE ANY TEMP. CONTROL. AND YOU CAN DAMANGE YOUR COMP. OR FREEZE UP YOUR SYSTEM.

[jawsplace]

That for the info. The fan rheostat switch does work through the full speed range from low to high. But when I've got the fan running above the mid speed that's when the clutch won't engage. Just so I understand, there can be an open circuit condition to the thermostat even though the fan will run up to max speed?

[fredsterra]

You have some "dead" spots it the switch where it sends power to the thermostat control.

I have 3-4 places in mine, and if you have the blower switch in just the right spot it will cut off power to the thermostat control. But if you move it up or down just a bit it willl work.

And yours is dead until a given point.

[jawsplace]

FYI... I kept working the fan speed knob back and forth and the area with dead spot became smaller and smaller. After a while the dead spot went away altogether. Now the compressor kicks in through the full fan speed range. I guess the switch just needed a few minutes of rapid turning to clear some dirt/corrosion. Always satisfying to get lucky with a quick fix like that.

[Dennis Bernth]

You can probably prolong it's life a little bit if you pull the front panel off the AC vent and use some contact cleaner on the switch and the rheostat both. 15 minute job but it makes a difference.