I have a 1990 accord ex.
I know the compressor is good because if I put 12v to it the air works good but the wire going to it never has power.
I checked the fuse and jumped the hplp switch. what else could it be?

 

have you checked to see if the switch mounted on the dash works. it could just be the ac relay. check to see if your getting full 12 volts to the ac wire. also might be the pressure swtich. it could be low in freon. or to high causing it not to turn on.

 

The switch in the dash works. I am not getting any power to the compressor and as I said I bypassed the hplp switch.

 

So my A/C compressor will not turn on. The system has a full charge and I have jumped the High pressure low pressure switch. The condenser fan wont even turn on and I have changed its relay. The fuses are all good and the green light it lit under the a/c button.

 

I was told it could be the thermistor what ever that is. What is it and where is it?

 

Your A/C clutch could be bad.

 

ok you say the dash button works. so now change the relay with a known good one and start from there. if it still doesnt start i would say broken wire somewhere.

 

Its fine