2003 columbia with bendix air Dyer

Is the system charged? If the refrigerant charge is low the compressor clutch will not receive power either.

 

Have you checked it with gauges? If it's overfilled it also will not work. Just because you added refrigerant doesn't mean it didn't leak out and it doesn't mean that you're not overfilled. If it is a Freightliner most of them take about five cans which is I think around 60 oz?

If your truck is set up the same as mine the binary switch is what actually controls the clutch coming on and off. You will not normally have electricity at the high pressure switch especially if it is a Freightliner because they generally have a separate module that controls the fan. When the switch opens it tells that module to command the fan.

You should be able to jump the wires with key on electricity without the truck running just to see if your clutch will engage. You should have electricity at the binary switch as long as the AC selector is in place with the key on. If you have electricity there and you have checked your pressure with gauges and you have jumped the wires and you see that your compressor does lock up then the binary switch is bad if your compressor won't start. Not sure if yours has a separate ground or not. Also again if it's a Freightliner there is an actual AC clutch relay that is in with the circuit breakers. If you have no electricity at the binary switch with the key on and the AC selected, then you have to look toward that relay..

Was everything working and now it just won't work? Did you add more to the system or did you drain the system and replace parts and then refilled? Did you use gauges?