Hman945

Hello...I too am experiencing some A/C issues with my 2010 Civic EX-L that are driving me completely nuts. I would greatly appreciate any help...
My problem: compressor does not come on but the fan inside the car does...does not blow cold air. When the compressor is jumped, it comes on and blows cold air. So far, I checked the fuse, replaced the the compressor harness thermal protector and the temperature switch. No success...I now purchased an evaporator temperature sensor as my mechanic seems to think this is likely the problem. I searched to determine where and how to replace this sensor with no luck. One site says you have to access the sensor from behind the glove compartment and blower motor and another site says its on the drivers side...
I'm at my wits end with this issue...any help would be greatly appreciated.

ezone

Turn on the AC system. See if both radiator fans turn on when you turn on the AC.

If they do, you probably need a clutch relay.

Hman945

Thanks for getting back to me about my issue...Neither fan comes on when I turn the AC on...The interior fan does, but the two fans be the radiator do not...what now?...Thank you

ezone

Check if the compressor plug is not latched (3 wire plug on top of the alternator). You can ohm check the thermal protector from that spot as well.


If it wasn't that......
Now you need to put a pressure gauge on to see if the system has leaked the freon out.

Also, look through the bumper openings at the condenser, see if it got damaged (punctured) by a rock or road debris. Sometimes this is really obvious, sometimes not.

Hman945

Thanks Ezone...You definitely seem to be the go-to person for all Civic problems...I will check the condenser this evening for any damage. The compressor plug is attached and I've already replaced the thermal protector. I will get my mechanic to check the system for leaks with his gauges...I will keep you posted and hope you stay tuned until this issue is resolved. It's been a frustrating experience thus far. GREATLY appreciate your help...

Hman945

Update on issue: I checked the connection above the alternator and it seemed fine. I looked at the condenser and it did not appear to have any damage or punctures. The mechanic who checks my vehicles is on vacation and cannot check the system for any leaks right now. He did however tell me that he does not think it does because when he jumped the compressor the fans and compressor kicked on and blew cold air. Is there anything else I can check?...I don't want to have to take to the dealer...Thanks Ezone.

ezone

What (connector or location) exactly was jumped here?

Hman945

The compressor was jumped directly to the clutch with 12 volts...it blew cold air in the car. However, the fans did not come on.

ezone

Was this done at the 3 wire connector on top of the alternator?


Since it got cold then we know it's got enough freon in it to run on its own. Not a low freon issue.
Need to figure out why it's not operating on its own.
You say you replaced a thermal protector...but is it electrically good? Continuity?

What part are you calling the temperature switch?

Ummm.......I'm guessing you don't have a scanner, a good one could quickly clear up a lot of question marks......
Do you have a volt/ohm meter and do you know how to backprobe a connector with a paper clip or T pin?

Hman945

Thanks Ezone for getting back..I'm not sure where (mechanic/friend) jumped it...he told me he just put 12 volts directly to the compressor at the clutch. I will confirm this tomorrow with him.
Items replaced:
- The thermal protector (AC COMPRESSOR WIRE HARNESS HONDA CIVIC 1.8 L 2006-2011 Thermal Protector A/C)

and the

- (Factory Air by Four Seasons System Mounted Pressure Transducer
MMJ25).
I did not check these parts for continuity as they were purchased new, but I probably should have.

I have a volt/ohm meter..I do not know how to backprobe a connector with a paper clip but with a little direction I can give it a try. Based on my answers to your questions you assumed correct that I do not have a scanner...Should I take the car to a dealer and have them put it on a scanner? Again, my mechanic will be away until Monday and I plan on showing him your instructions to further troubleshoot. Greatly appreciate your help.

ezone

Googled: LINK

(OMG they made it even better LOL)

The reason for backprobing is to take live measurements while a circuit is active and in use, without taking apart a connection.



Why was the pressure transducer replaced? Got a pic or a link?
First hits when goggled were for pepboys.
Is it fully plugged in?

Hman945

Thanks for the Internet Tutorial...LOL...I so deserved it.

Below is the link for one of the items I replaced:

https://www.pepboys.com/product/deta...01.8L%2520SOHC


I never usually buy aftermarket parts, but the thinking was by my mechanic was to replace the least expensive and most obvious sensors with the hope that it would resolve the problem...As we now know, it did not. As far as I know, it was fully plugged in, but unfortunately, I will not see him until Monday. I will also attempt the backprobing as you suggested over the weekend. I will keep you posted and hopefully have more info for you on Monday...My apologies for being so limited with info but I have to get the steps that were taken thus far by talking to my mechanic...Maybe I should get him to join this forum. Again, Thanks for your help.

ezone

What, no prayer? Hope and prayer should be done at the same time, they go together.

Obligatory:



If one understands how this stuff works-- and works together, one can then begin to formulate a strategy to figure out how to diagnose and prove what isn't working.
Do you mean you're just gonna try to figure out how? I was thinking of some specific checks to be done.

Specifically, take voltage readings on both sides of the thermal protector circuit while the system is turned on and engine is running, and take a reading from the pressure sensor you replaced (signal return voltage).

Hman945

Yes...I knew when I was writing my post to you I was going to get scolded for the "throw parts at it" strategy...It's just not the way to do it.

However,

I will do as you said and I will report to you on Monday...Thank you sir.

Hman945

Hello All,

Thanks Ezone for taking the time to help me with troubleshooting...
I ended up taking the car to the dealership to diagnose the probem.
Their findings:
VEHICLE IS IN NEED OF THE ECM/PCM - NOT SENDING SIGNAL TO THE A/C SYSTEM.

I was given a price of $977. for the new ECM/PCM and programming. Needless to say I was floored. Is this something that can be done outside the dealer? and is a used ECM/PCU a consideration?

As always, Thanks for help.

ezone

Wow.
I sure hope that's an accurate diag because they have been quite reliable IMO and sure aren't cheap...I'd hate to hear that didn't solve the problem.

Sometimes there's no workaround for not having a scanner that can display certain information, sometimes that is what is needed to confirm a suspicion.

Price quote is reasonable IMO -- if the diag is accurate.
(A compressor replacement would be a similar expense so take that into consideration.)

I've never been tasked with installing a used PCM, so can't comment. (short answer)
IDK if you can easily locate any other shop (Honda specialty shop) that could program a used or new PCM to the car (and if necessary update it to current Honda software level).

Is your car less than 8 years/80,000 miles?
Are you in California?
Check your warranty literature in the glovebox.

Hman945

Thanks Ezone...I live in NJ and the Civic is a 2010 with 72,000 miles. I checked the warranty manual with the car and it does say, under the title, Fuel Injection System, says the following: Engine/Powertrain Control Module (including Barometric Pressure Sensor and Software upgrades) warrantied for 8/80. Not sure if this applies but will be calling Honda today...keeping my fingers crossed. Thanks Ezone, I'll keep you posted.

ezone

That's what I wanted you to read.

Now it will hinge on the original in-service date to see if you're still within the 8 year time frame.
Bonus points if you are the original owner too, maybe you still have this in the paperwork.

Hman945

I want to thank Ezone for taking the time to help me troubleshoot my A/C issue. It was clear from the beginning of my post that Ezone is the go-to person on this forum in helping others with their Honda issues...My repair was covered under warranty (barely)...Honda replaced the Engine/Powertrain Control Module and the car is now blowing cold air!...Thanks again Ezone

ezone

Boy, I'm so glad that worked out well for you!

PCM is not a typical failure IMO. I'm glad you got a correct diagnosis.