eksedan7198

I purchased my 1998 civic lx and have noticed that no matter what, anytime the car was turned on the a/c compressor and condenser fan were constantly running. I then replaced the a/c harness with a new one and now neither the compressor nor condenser fan will come on.

**Disclaimer: I am by no means an expert with electrical so please bear with me

I looked at the wiring harness for the a/c system and noticed that the previous owner had "rigged up" and spliced a ground wire from the chassis to the blue/white wire of said a/c harness.





The wire on the a/c harness that was spliced into and connected to the chassis ground is the blue/white wire located on this plug.



i removed the chassis ground wire from the blue/white wire, and neither the compressor nor condenser fan will come on.


- I checked underdash fuse #17, and it is fine.

- With the ground wire attatched to the blue/white wire, the condenser fan and compressor will stay engaged, regardless of whether or not the "A/c button" is on or off.

- After much despair, I purchased a new a/c harness in the hopes that it was faulty/hackjob wiring that was the issue. (The pen in the first pic is pointing to the plug in discussion.)





After replacing the old harness with the new harness, i discovered that neither the compressor nor condenser fan will engage.
- underdash fuse 17 is still good
- fan/compressor will NOT engage, regardless of on/off position of a/c button.


What could be the cause of the compressor and condenser fan not engaging when i replace the original "hackjob" harness with the new oem unit? Any suggestions for additional troubleshooting?

Thanks in advance!

( As previously stated i have basic electrical understanding and am somewhat familiar with the honda ac system. )

Former User

I edited your thread title to reflect the current problem.

Did you connect the G751 ground wire on the new harness?

Locate the 3P connector (Blk/Yel, Blu/Red, Blu/Wht wires) for the A/C thermostat behind the glove box. Unplug it and ground the Blu/Wht wire terminal in the connector to the metal frame under the dash. When you turn the key to the ON(II) position, does the condenser fan now run?

eksedan7198

I used the old a/c harness with the ground to the blue/white wire for this troubleshooting. (I'll refer to that extra ground as the "ghetto wire".

I first grounded the a/c thermostat blue/white wire and turned the ign. To ON(II) position and the fan stayed on.
(This is with the "ghetto wire" still attached to the a/c harness.)

Next, I took the ghetto wire off and tried it with just the a/c thermostat grounded and the fan stayed on, I unplugged the ground while the car was still in the on position and the fan cut off , just to make sure I had a good ground.

I then next hooked the ghetto wire back up and left the a/c thermostat unplugged with no ground to the thermostat and the fan remained on. (Not sure if that is how I was supposed to test that method???)

Whats next boss?

Former User

You don't want to use the old molested wire harness so remove it and install the new unmolested wire harness and connect G751. Then redo the test.

eksedan7198

Ok will do later today and I'll let you know my results.

To answer your older question I did have the G751 ground wire grounded when i used the new harness the first time.

eksedan7198

Alright! I put the neww harness on and grounded that blue/white wire and the condenser fan stays on in the ON (II) position. And when unplugged ground the fan shut off.

eksedan7198

I grounded the ac thermostat blue/white wire just to make myself more clear.

Former User

Now plug the A/C thermostat connector back in and unplug the 14P connector at the rear of the heater control panel. If you ground the Blu/Red wire in the connector, does the condenser fan run with the key in ON(II)?

eksedan7198

Im having a hard time locating the 14p connector is there anyway you can tell me where its located exactly (possible color of plug.)

eksedan7198

Pictures would be awesome

Former User

You need to remove the heater control panel to access the 14P connector. Steps 1-4 in diagram below. The connector is green.

eksedan7198

I grounded the blue/red wire on the 14 pin connector and the condensor fan does indeed stay on with the key in the ON(II) position.

Former User

Your tests indicate that the heater control panel is bad. Replacing it should make your A/C work properly. Scout some junkyards.

Does the A/C blow cold when the Blu/Red wire is grounded?

eksedan7198

I didnt crank the car up, I was about to go to bed but I'll check and see if the ac blows cold real quick with that wire grounded.

Former User

If so, replacing the heater control panel will restore you with a fully functional A/C system.

eksedan7198

The ac was blowing cold while holding the ground to the 14p connector, I'll try and make time to go to junkyard and put my car back together! I'll keep you updated, thanks for all your expert troubleshooting!

Former User

eksedan7198

So my new heater control panel I ordered doesn't fit with my stock harness, the 14p connector on the new one is a little smaller so my 14p connector won't fit into the plug.

Former User

Did you order the wrong one?

eksedan7198

Disregard the last post . Lol I was being a noob and rushing putting the new one in because it started pouring down raining, but after it stopped went bavk outside and plugged that baby in and started the car and crossed my fingers slid it to cool and pressed the ac button and the compressor kicked on! I'm so happy now!!!!! Thanks a lot again Ron! Now only to fix my passenger power window and my car will be FULLY working!

Former User