I just acquired a 2000 civic sedan EX and the AC is non-operational. here's what i know:

I turn on the blower and press the AC button: condenser fan runs and engine idle does not change. (I have had a P0505. Cleaned IAC valve but i dont think it solved it.)
I got a can of Freon from auto zone and connected it to the low side. gauge said 110PSI w/o adding freon. So I don't think it's leaking.

I started to do the "compressor clutch not engaging" troubleshooting in the service manual and I have voltage at one contact of the compressor clutch relay and ground at the other (says wiring and clutch is not open). If I "short the contacts of the relay" I hear no click from the compressor but i do get a spark and it's drawing 3.5 amps (according to my DVM.) Is this enough to engage the clutch?

2nd problem I found. I dont have voltage at ether coil contact of the clutch relay but i do at the condenser fan relay. could this be a internal problem to the under hood relay box?

 

Static pressure tells you little about the refrigerant level.

The relay has 4 terminals. Two should be hot with key in ON(II). Check that.

Also swap the fan and clutch relays to see if the clutch engages.

 

I did. Only the contacts is hot. Not the coil.

All relays work. I swapped them around and all work in the radiator fan slot. Got a new relay today to no avail.

 

What's the answer? Are 2 contacts hot?

 

only 1 contact is hot.

 

With key in ON(II)?

 

i have 12v at each red circle on the blk/yel wire with the key on.

 

No voltage at terminal 2 of both relays? If so, check fuse 56.

Also no voltage at terminal 4 of the clutch relay?

 

fuse 56 is good because the condenser fan runs when the AC is turned on.


correct.

 

Is there voltage at terminal 2 of the clutch relay?

 

yes. If i short terminal 1 & 2, I hear no click from the compressor but i do get a spark and it's drawing 3.5 amps.

 

1) The hood fuse box is bad. Replace it.

2) Unplug connector C214.

Run wire from (+) post of battery and supply voltage to Red wire pin 6 in the male pin side of C214. Does the compressor clutch now engage?

 

i've been sick these last few days.

1. I took apart the hood fuse box and was able to fix it. I have 12v at terminal 4 of both relays now.
2. i unpluged C214 and ran a battery + post jumper to pin 6. no click from the compressor. draws same 3.5 amps. i unplugged the compressor from the harness (C752) same jumper same 3.5 amps. no click. no change.

 

What was the problem? Is a 20A fuse installed in the fuse 56 slot?

Okay.

For this test, did you again jump voltage to C214 pin 6 or instead to the C752 red wire (compressor side)?

 

i think the spade terminal inside was loose. i tightened it with plyers and it feels better now. yes fuse 56 is a 20A.

i bypassed the car wiring and jumped the compressor directly at C752 (compressor side).

 

Ohm test the compressor coil. Also test for a short to ground. It's likely bad.

 

Coil is /was good. clutch was mechanically seized.

I just took it to the shop and got a new compressor w/ warranty.

Thanks for your help Ron

 

Glad to know you found the issue.

Can you give more details about the failed clutch and/or post some nice pictures?

 

The clutch was sized in a way where the belt and the compressor turned freely but the actual engagement was sized. The coil simply wasnt strong enough. Mechanic took the old compressor for the core charge so no pics unfortunately.

 

Im having almost the same issue but I do get 12v to pins on the clutch relay but the signal ground coming from the ecu when I turn on the fan blower and the ac button