Intermittent Air-Con Issue

Hi Guys,

Another issue that decided to rear its ugly head this morning was my Air Con. It was set to 19 and the car was clearly warmer than 19 in the cabin, yet it was kicking out some HOT air. Kicked out hot air all the way down to 16, in fact it would only blow cold when set to "Lo" but this wasn't chilly, air-con cold, just not hot (if you know what I mean).

This happens from time to time, summer and winter. You turn the engine off, restart the car and it normally remedies it. Is this maybe just an air-con re-gas, dirty thermostat or something potentially more worrying/costly?

Thanks again guys,

Steve

I has this recently, had it re-gassed but still the same. turned out to be leaking from the pipe entry and exit pipes on the air-con pump.

Seals were £3.65 each plus an hours labour (JCB Honda Ashford) this included a free re-gas.
On the first re-gas they added some UV dye so were able to see the leak on the second visit.

Seems OK now but advised that the pump valve keeps operating and this would require a new pump at circa £900!

Steve

On one hand, I'm not sure, as if I turn the engine off and on again, it normally, not always, but normally remedies the issue, which makes me think it could be something electrical, not registering properly or something.

On the other hand, this does sound like you could be onto something. It normally happens when it's colder in the mornings, as if the cold over night has caused the seal to contract a little and allow some escaping of gas when all is fired up.

To be honest, I don't really understand how Air Con works and I don't see how this could cause the air to blow hot, but if you had the same problem and remedied it rather cheaply, I'll just ask them to replace the air con pump seals when it gets serviced in January. This doesn't happen a lot and in the winter I tend to set the temperature to 21 or 22 which I wouldn't have thought would engage the air con pump.

Is it blowing the same temperature on both sides?

Yep, basically, just occasionally and it only happens when it's been a cold night and the car's sat all night without being driven.

Here's the issue in more detail. The air con is normally set to 19, 20 or 21, either set to a force of 1 or on auto. But when this happens it's just blowing warm almost hot unless I select "lo" in which case it just blows with what feels like no heater/air-con intervention at all. You know like when your old car didn't have air con, you set it to the blue setting and it just blows cool air without the heater being on, it's like that on "lo".

But as soon as you select a temperature above "lo" such as 16 degrees, it blasts out warm, almost hot air. And it's not that my cars colder than 16 and the auto is trying to warm things up, I'm sure of that, as this has happened when set to 19 degrees and needed, as despite it being very cold outside, the sun was streaming in and the cabin was roasting.

I hope that better explains the symptoms.

Stevearcade said:

Yep, basically, just occasionally and it only happens when it's been a cold night and the car's sat all night without being driven.

Here's the issue in more detail. The air con is normally set to 19, 20 or 21, either set to a force of 1 or on auto. But when this happens it's just blowing warm almost hot unless I select "lo" in which case it just blows with what feels like no heater/air-con intervention at all. You know like when your old car didn't have air con, you set it to the blue setting and it just blows cool air without the heater being on, it's like that on "lo".

But as soon as you select a temperature above "lo" such as 16 degrees, it blasts out warm, almost hot air. And it's not that my cars colder than 16 and the auto is trying to warm things up, I'm sure of that, as this has happened when set to 19 degrees and needed, as despite it being very cold outside, the sun was streaming in and the cabin was roasting.

I hope that better explains the symptoms.

Click to expand...

Hi Steve, do you still have this issue ? If so, it could be several things, most probably the relay that pulls in the compressor, or possibly you have a perished condenser. If you drive at 70mph on a cool day with the temp setting at lo or 16, if it blows cold air, then it is the condenser. If it never blows cold any more, then with the engine running, you need to look down at the compressor, and if it is not turning, then it is most probably the relay that pulls the compressor in. Cheers, Brian

Is the outside temperature reading ok? I had this sensor go faulty and when it was thinking the temperature was -20 in the middle of the summer That affected the climate control somewhat!

It comes and goes. I'm still trying to figure out exactly what circumstances trigger it (if any :unsure: ). The temperature reading makes sense on the dial, I don't think that's wrong. I'll keep an eye on it and let you know.

Stevearcade said:

It comes and goes. I'm still trying to figure out exactly what circumstances trigger it (if any :unsure: ). The temperature reading makes sense on the dial, I don't think that's wrong. I'll keep an eye on it and let you know.

Click to expand...

If it comes and goes, then it's either the relay or the consenser is perished.

To check the condenser, look through the lower grill at the front of the car and you will see what looks like an engine radiator. That is the condenser, it is in front of the engine radiator, it acts like the engine radiator for the A/C, in that it loses heat into the air flow when the car is moving or the fans are blowing. If you look you will porbably see that the bottom half has loads of gaps (its perished) whereas the top half is not so bad. If that it what your condenser looks like, then it is very inefficient.

tf your condenser is not too bad, the only other similar effect is low refrigerant pressure, Halfords will check the pressure for you for £10.

If your refrigerant is OK, and if your condenser is OK, then if the problem comes and goes then the relay that pulls the compressor on and off has bad contacts. I measure the current that the electric clutch on the compressor takes, and it is 3 Amps, which is quite a lot IMO for a small relay that clicks in and out all the time when your A/C is on cold.

EDIT: here is a pic of the perished condenser on my car with bumper removed, note the difference between the top half and bottom half, the latter looks like some slats !!

I have the intermittent aircon problem as well. From reading around, the prime candidate seems to be unreliable relays and the problem seems to occur on other Honda models.

From other forums, if you are having this problem try switching the two a/c related relays to see if that helps. This shows you where to find them:
http://mechanics.stackexchange.com/questions/13022/honda-accord-2005-headlight-relay-location
The a/c relays are the top middle (between the two blue blocks) and the bottom left.

If you want to try replacing them, the part number is:
39794-SDA-A05.
My current ones are made by Mitsuba, which I understand to have replaced Omron relays. Ebay immediately brings up many results, cheapest I've seen is £1.38 (Hong Kong) up to about £35+, but for a UK seller most results are around £18.

Here are some of the other forums with further details:
http://honda-tech.com/honda-civic-2001-2005-78/c-working-intermittently-some-days-hot-some-days-cold-searched-2589540/

http://www.driveaccord.net/forums/15-7th-generation/48332-intermittent-ac-problem.html

http://www.civinfo.com/forum/bugs-faults-irritations/73473-updated-air-con-compressor-relay-prevent-failure.html

So far, I've tried switching the relays and tried the air con a couple of times and it's working thus far but given the nature of the fault, this doesn't really give me confidence that the problem is fixed. So I'll be ordering a relay or two and see how I get on...

Hope this is useful.

When I bought my Accord the A/C was not working, here are the steps I took to get it working.

1) A/C on... No cold air and the A/C compressor was not kicking in
2) A/C re-gas... Showed no leaks, however, the A/C compressor still did not kick in
3) I swapped the A/C relays around and boom... A/C working again
4) I managed to get 2x cheap OEM relays from a private breaker (decided to get a spare for backup as they were super cheap)

Hope my experience helps

SiC's very helpful post above from 7th May 2016 solved this same issue for me (thanks SiC!) on a 2004 Accord Tourer 2.2 CDTI Exec.

I could hear and feel the fans working, but the aircon system was unable to cool the air on hot days and simply blow air at whatever the ambient temperature was - even when set to 'Lo'.

I swapped the relays as suggested by SiC and it immediately began working again, cooling the air ice cold when set on 'Lo'.

I include below a photo of the under bonnet fuse box with the 2 relays highlighted in red in case it is useful for anyone else. Please note this was taken *after* I'd swapped them around, so 7001 4422 was originally lower left and 7001 4511 was originally top middle.

Also, I'm curious as to what the long-term effects of swapping these relays is? Does it matter that they're slightly different part numbers? Should I be looking to replace like-for-like and swap them back? Hopefully someone with more technical knowledge than me can explain!