I'm having trouble with running a A/C on 99 civic lx. I did some quick diagnastic so far this is what i got. When I turn on the A/C, I get a hot air. The frione is in the system. When dialing the tempature between hot and cold there is no difference. A/C fan does not run when i turn on the A/C.

So what could be the problem?

 

So neither the heat nor A/C work, right?

Heater: Check the cable running from the heater panel to the heater valve located near the heater hose on the firewall. The cable may be disconnected.

A/C: Check whether fuse 56, 47, or 17 is blown.

 

heater works fine. it blows hot air regardless A/C is on or off..

 

Did you check the three fuses? If they are fine, check whether jumping power at the relay to the condenser fan or compressor clutch makes them run.

 

i notice when dialing the temperture control above fan control doesn't seem to work.. regardless dialing to cold or hot, it keeps blowing hot air @ same temperture. there is absolutely no difference.

 

Did you read my suggestion in post #2? THE HEATER VALVE ON THE FIREWALL MAY BE STUCK OPEN.

Have you check the three fuses?

 

checking your fuses like ron suggested is your best bet.
i had the same problem and it was the fuses in the bay