AC and Cooling fans

[captndave737]

I'm a little confused on the wiring. I'm looking at the schematics and it only shows 2 switches; the high pressure cutout switch located in the cooling line near the generator and the pressure cycling switch located on the accumulator dryer. I can't find the other switch that is located in the back of the compressor or how it's wired in.

When I plug in the switch located in the compressor, I think it's an over pressure switch, my cooling fans run continuously and it doesn't matter what position the AC controls are in including off. When I unplug it the cooling fans come on at the 170 deg. programmed in my chip. I have the factory manuals and can't find this switch anywhere!!!

 

[RmvBfrFlght]

Sounds like someone did some rewiring of the fans. As for the pressure switch (3-wire) to operate the fans, it is located in the high pressure line near the compressor.

RemoveBeforeFlight

 

[pacecarta]

that red switch uses the same ground line as the fan but it should not activate the fan relay or cause fans to run
that hi presure switch is normally closed and opens when theres an overpressure to cut off the ac clutch to prevent operation of the compressor

 

[captndave737]

Fans were rewired by me years ago but this has never happened. I basically have the fans hot-wired. High speed fan relay and delay relay gone. It's wired so both fans come on when the low speed fan relay closes.

I also made a new wiring harness this winter when I was rebuilding the engine. Everything else is working correctly. Since I lengthened some wires and shortened a bunch more I'm guessing I may have screwed things up between the High Pressure Switch and the High Pressure Cut Out Switch. Should be easy enough to trace.

In the component location in the Service manual it shows the HP Cutout switch in the refrigerant line and it doesn't say where the HP switch is. I think that messed me up when I was re wiring. It's now obvious it's the HP CUTOUT switch in the compressor and the HP Switch in the coolant line.