roger t

09 Civic LX 18K miles. Twice now on 300 plus mile trips, the ac works great the 1st 200 miles, suddenly only warm air & the blower puts out less air. All controls are set at "max". Just prior to losing the cold air, there seems to be a "tinkling" sound coming from the vents...ice maybe ? This kinda reminds me of the "old days" when the evaporator would freeze up. Around town, the ac will freeze you out of the of the car. A bypass relay maybe ? If it is a relay, where is it located ?
Thanks,
Roger

jordan1794

Would definitely check to make sure the unit isn't freezing.
When it happens pull-over and open the hood and see if you can see if there is a lot of condensation on the unit, and if you can see ice anywhere.

I believe the AC stuff is located on the passenger side of the engine, under the power steering fluid and what-not.

ezone

Evaporator freeze up.
Most common cause is the clutch relay stuck on.
(Rare cause might be evap temp sensor issues, and HVAC control panel issues.)

Same issue will kill the battery overnight.....and cause the system to burp out clouds of freon at stops.

Updated relay available: Ask your Honda parts department for Honda part number 39794-SDA-A05

jordan1794

Just curious e-zone, if my 2006 is NOT having this problem, do you think it'd be wise to replace the relay anyways, just to make sure it doesn't act up down the road?

ezone

Your choice, I guess.
It's a common issue, and has been for many model years.


Original relay brand is omron?
Updated relay is MITSUBA



The omron relays are dirt cheap and have been used all over many of the cars for all sorts of stuff. The AC clutch seems like the main location that causes issues, although I have seen the occasional sticking relay in other circuits--park lights comes to mind.

roger t

Thanks for all your help. I think I will go ahead & replace the ac clutch relay & see what happens. Last question...which relay in the fuse panel is it ?
Thanks,
Roger

ezone

Copied from another post




(Engine compartment fuse and relay box, Left half of the pic) The relay in position #5 is the clutch relay.

The new and improved relay is about $30. The original design is much cheaper.
Updated relay brand is MITSUBA
Updated Honda part number is 39794-SDA-A05

HTH

roger t

Thanks for the info...bet this fixes my problem. No fun driving I-35 at 70mph with the windows down & the temp is 103 degrees.