This should be an easy on for somebody here - which one is the low pressure side? I think it's low on R124 and wanted to top it off. I have the one hose gauge that you put it in with. What's the max low side pressure it should be?

 

On which vehicle? On your 99 it is R134a and you DO NOT want to put R12 in there.

 

I didn't realize how little info a gave until you mentioned it. Sorry - it's the 99. And I meant to type 134a, somebody must have been talking to me (posted from work) when I sent it.

 

The low side port is on the accumulator. It is located just outside the heater box, and the line off it goes into the compressor.

 

your low side port is the larger of the two ports. your pressure changes depending on air temp.,if the a.c. clutch is ingaged or disengaged.If you you have to add freon to the system than you have a leak somewhere in the system.If you want to top it off then you can but if you end up with more in the system than required total amount than you will actully lower your a.c. capabillitys

 

NO IT'S NOT! Low side is the smaller one! It's on the accumulator like Kordog said....jeees.