Bypassing a low pressure sensor is a perfectly good method to troubleshoot the system, and if bypassing the switch allows the compressor to kick in, you're in good shape (sort of). The low pressure sensor is there to prevent the compressor from running if the pressure level is below the sensor set point. This is to protect the compressor. You should check the operating pressure in the system to determine if the problem is a faulty sensor, or if indeed it's doing its job. If it's just the sensor, replace it.... don't leave the bypass in place. The sensor is an on/off switch, which is normally closed.... a simple check for continuity (zero resistance) with a multimeter or test light, will tell you if the sensor is good or not. Don't run the system unless you're very certain that the refrigerant charge level is correct. The oil that lubricates the compressor will be lost if the refrigerant charge has leaked out, and running the compressor for any length of time without proper lubrication will allow you to ruin the compressor, thus testing the smooth operation of your bank account. Good luck

Marty

'96 855T