I have a 98 civic. The compressor will sometimes not kick on at all, and sometime it will sit there and kick on,off,on,off and sometimes will stay on for a few minutes. Pressure is good as far as freon goes. I took the connector to the pressure switch off and jumped it and the compressor did nothing. Grounded the blue/red wire of the connector and still did nothing.

So i'm wondering if maybe it's just a clutch issue. I'm not familiar with a/c systems and it's kinda hard to see down around the compressor, how do i tell if it's getting continuous power? Thanks

 

If you remove the clutch relay in the hood fuse box and jump terminal 1 to terminal 2 in the relay socket, does the compressor clutch now engage continuously? If so, remove the jumper wire after a brief test to avoid damaging the compressor.

 

Low side pressure should be around 100 psi when not running and the system is cool. If you jumped the pressure switch conntector that eliminates high or low pressure problems so you need to look elsewhere. If the clutch is not engaging then pull the red wire going to the clutch and and check for battery voltage, the engine has to be running and the AC set to on to do the test. If no battery voltage check the clutch relay, usually the AC fan relay and clutch relay are the same so they can be switched around, check the part number on the relay case before switching. If there is still no battery voltage to the clutch it could be the ECU is not firing the clutch relay or the thermostat is acting up or ?

Tim

 

I didn't try jumping that yet, but i did switch the relays with the one beside it (for the fan i think) and didn't make any difference. And the fan continued to run fine. I just bought the car yesterday. The pressure on the low side was around 50 i think. But it was around 95 degrees here today. Don't know if thats to high or what. But i don't think that should matter since i jumped the pressure switch and didn't change anything.

 

If you jump the relay and the compressor clutch continues to engage and disengage, then the armature plate gap of the compressor clutch may be slightly too wide. If the clutch engages continuously, then check whether voltage reaches the ECU from terminal 3 of the clutch relay.

 

Don't jump the compressor with the engine running! Ok to do it with engine stopped, listen for clutch to pull in. The contact circuit of the compressor relay is always live, no need to turn key on even.

Plug everything in as stock and see if the idle speed increases when the condenser fan starts. If the idle is too low, the ECU will refuse to engage the compressor. If idle speed increases, check if the compressor red wire is getting power. If you have power to the compressor but it doesn't engage, clutch gap may be too wide.

Like the other guy said, pressure with the compressor off should be more like 100. If you only have 50, the system is basically empty.

 

the pressure was 50 when it was running and engaged.

 

Well it was working a little better today but was still kicking on and off about every 45 seconds or so. So i decided to try and jump the pressure switch again with a different wire and it stayed engaged for a good 3-4 minutes before i turned it off. So could it be something with the pressure switch itself or maybe the high side pressure?

 

Quit jumping stuff.

Does the condenser fan work? Any possibility it's been overcharged? You need to actually measure the high side pressure to see if it's a high pressure issue. The switch is on the high side, it won't cycle because of low pressure.

 

lol sorry, easiest and fastest way to eliminate problems is to do a quick jump. And i never checked the high side, and i thought the switch was for the low side?? Which is why when the low side is low or empty the compressor will continually cycle on and off. If the switch was on the high side the the low side pressure wouldn't affect the compressor?