[bigrick56]

1999 7.3 superduty the air goes off and at will. i have bipassed both hi and low switches. it has power going to the switches and the pump. does this thing have a thermostat switch inside of the cab. does the cab have a filter thanks

 

[RT]

Cabin filter was a dealer installed option - I've never seen one - just read about them.

Biggest cause of intermittant engagement is the air gap - View attachment airgap.pdf

Double check the connection to the clutch - sometimes that plug gets corroded. If jumping the low pressure switch doesn't cause it to engage, and there is power to the connector - the clutch gap is either too great or the electromagnet is going out.

 

[bigrick56]

Cabin filter was a dealer installed option - I've never seen one - just read about them.

Biggest cause of intermittant engagement is the air gap - View attachment 11739

Double check the connection to the clutch - sometimes that plug gets corroded. If jumping the low pressure switch doesn't cause it to engage, and there is power to the connector - the clutch gap is either too great or the electromagnet is going out.

The plug is good so i guess i have to look at the air gap thanks

 

[DR435rider]

My truck had the same symptoms. AC clutch was bad. Fixed it and no problems since.

 

[375.0ford]

I would agree with the compressor clutch, the coil in the clutch looses is abillity to pull the drive dics in to engage the compressor, you can ck voltage at the plug on the compressor if it stops cooling and see if you have voltage, if so, the clutch needs to be replaced.