Morning all, question to the group. '06 LR3 190k miles AC stopped blowing cold. Hooked up gauges and had 0 pressure on both high and low side. Had bought and installed a pressure switch online cheap and wonder if maybe that's why. What is the difference between a $29 pressure switch and a $129(+) dollar pressure switch besides $100....also on a clutchless system with compressor running constantly what gets activated by the pressure switch..thank you in advance

 

Morning all, question to the group. '06 LR3 190k miles AC stopped blowing cold. - Are you talking about the pressure sensor on the refrigerant lines on the left side of the engine near the left battery box?

Hooked up gauges and had 0 pressure on both high and low side. Had bought and installed a pressure switch online cheap and wonder if maybe that's why. - No pressure on high or low side MIGHT be that the system is out of gas. or it could be that the valves are closed on the gauges, or the schrader valves in both the high and low side may be stuck shut. Can you pull a vacuum on the system. What do you get with the gauges hooked up when the engine is off?

What is the difference between a $29 pressure switch and a $129(+) dollar pressure switch besides $100.... - What brand and part number did you get?

also on a clutchless system with compressor running constantly what gets activated by the pressure switch..thank you in advance - The LR3/Discovery 3 uses a Denso 7seu17c compressor. The compressor is a wobble type pump. It changes the volume of gas based upon the angle of the plate which is controlled by a solenoid that moves the plate angle to change the amount of volume (i.e. pressure) put into the high side. Make sure you have power to the solenoid as well.

 

So just to clarify, after you swapped switches you did recharge the system?