my a/c has worked fine until a few days ago. It still has pressure(I don't know how much)but when I turn it on the compressor does not come on. but if I jump the a/c relay b1 to b4 it will come on. what is wrong ?

 

start by changing that relay

 

If that doesn't work, you might try to reset the PCM.

 

I have swaped out the relay and it still does it ,I will try and reset the pcm.

 

ok I reset the pcm and it worked.why did it do that? anyway thanks for the help now I don't have to sweat my *** off any more

 

Just for future reference, I had the same problem once and it turned out to be a clog in the system. I jumped the relay and it burnt out the clutch. Now I have no A/C

 

I don't know why. My friend had the same problem and this is how we fixed it.

 

The PCM monitors the AC pressure level; if the level is out of range, the PCM won't allow the compressor to kick on.