How do I manually engage the clutch. I know that I can disconnect the power supply plug and run it from the battery, my question is if perhaps I can unplug the relay or do it thru the low pressure switch. My a/c is not working, so I am doing a complete system flush, a full vacuum, add 4oz. of compressor oil and 32oz. of 134a. Please let me know if these sound correct....

 

I have a 2003 Disco 2, it's in my profile but just in case

 

if you do pull a complete vacuum on the system, you may not have to jump the low pressure switch it may take enough refrigerant with out jumping it.
LPS "i" believe is on the drive side of the radiator next to the filter drier. you may just try jumping the LPS and adding gas rather than a complete evacuation.

 

Got up early, by-passed the compressor (thanks Drowssap you are the man) did a full vacum and load up the system with fresh 134a. After 45 minutes, low side 35/37 and high side 180/200 perfect reading for the ambient temperature. Inside feels nice and cold, electric fan working as it should and not overheating coming from the engine 190° stand still, a/c on full blast. Life is good but as we all know tomorrow something WILL happen.

 

glad to hear it