JD 4030 air conditioning compressor not engaging

[jeffharp]

Hello,
I am having a problem figuring out what the compressor is not kicking in. I am not getting power to the compressor. So I tracked it back and determined that I was not getting power to the thermostat in the cab. One of the wires going to the thermostat comes from the blower switch. Since no power was going to the thermostat, I assumed the blower switch was bad. I replaced it, and the same result.

Probably unrelated, but there is no power going to the radio and one of the blowers does not work when on high.

Am I on the right track? I do not have a wiring schematic, so any help would be appreciated.

Thanks jeff

 

[fuel doctor]

Hello,
I am having a problem figuring out what the compressor is not kicking in. I am not getting power to the compressor. So I tracked it back and determined that I was not getting power to the thermostat in the cab. One of the wires going to the thermostat comes from the blower switch. Since no power was going to the thermostat, I assumed the blower switch was bad. I replaced it, and the same result.

Probably unrelated, but there is no power going to the radio and one of the blowers does not work when on high.

Am I on the right track? I do not have a wiring schematic, so any help would be appreciated.

Thanks jeff

It could be a pressure switch that is not letting power threw. on the blower there is a resistor that goes bad and want let it blow on high

 

[RLstangs]

Bad cab connector under the right front corner of the cab when sitting in the seat. Remove filler plate at the rear of the right side battery and the connector is behind the filler plate.

 

[jeffharp]

Bad cab connector under the right front corner of the cab when sitting in the seat. Remove filler plate at the rear of the right side battery and the connector is behind the filler plate.

I will take a look tomorrow. Thanks

 

[jeffharp]

It could be a pressure switch that is not letting power threw. on the blower there is a resistor that goes bad and want let it blow on high

Once I get it cooling I will work on getting the blower working right. How do I get to the
blower?

 

[Tx Jim]

Once I get it cooling I will work on getting the blower working right. How do I get to the
blower?

Raise cab roof then remove a bunch of screws that attach a metal cover to access blower motor,evaporator & heater core. On AC not working 1st thing I would do is check the coolant(freon) pressures before looking for something electrical

 

[jeffharp]

Bad cab connector under the right front corner of the cab when sitting in the seat. Remove filler plate at the rear of the right side battery and the connector is behind the filler plate.

See the connector. Which wire should be supplying the power?

 

[jenkinsph]

Raise cab roof then remove a bunch of screws that attach a metal cover to access blower motor,evaporator & heater core. On AC not working 1st thing I would do is check the coolant(freon) pressures before looking for something electrical

I agree with Jim on this as most systems I have seen will disconnect the clutch to the compressor if it gets too low on Freon. Curious is this an R12 system or has it been converted to R134a?

 

[RLstangs]

The terminals burn in the connector. There is two power wires to the top of the cab from the connector. The blower motors on low speed split the power through one motor then to the 2nd motor from one wire to run at half speed. On high speed each blower has its own power. If there is no power for the AC clutch and one blower motor on high, one of the power wires has no voltage.

 

[RLstangs]

The AC compressor has a thermal limiter (fuse) at the compressor that burns out if low on freon, little square black box with three wires under the compressor. Check to see if if it is melted or if there is power on one of the three wires with the AC on. If no power, check the cab connector. If both blower motors work on low speed the motors are OK.