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updated air-con compressor relay to prevent failure

AC/Heater 
392K views 643 replies 222 participants last post by  culzean 
#1 · (Edited)
This is a common cause of failure of the A/C on our civics.

In fact just a week ago Honda issued a Bulletin about it. The original fit Omron relay is suseptable to moisture ingress. This can form nitric acid in the presence of the normal arcing as the contacts operate. This will lead to corrosion and eventual failure. The Bulletin warns that the relay can fail either open or short circuit. If the latter this forces the compressor on to 100% duty cycle and can burn it out.
The remedy is a replacement relay from a different manufacturer - Mitsuba - that is a better quality item. The bulletin warns that the EPC is not yet updated, so you have to order this countermeasure part number directly to recieve the new part, otherwise you will just get the "old" part. I'm surprised they are not doing a campain over this considering if can fail in a way that might lead to screwing up other parts of your aircon

This the bulletin number:-

SM-10-002-00

It affects ALL civics (and CR-V and jazz) upto and including 2011 model year

Here is the countermeasure part number:-

39794-SDA-A05

RELAY ASSY., POWER (MICRO ISO) (MITSUBA)



The datasheet for the original Omron part is here:






The specific part is G8HL-H71 which appears to be a Honda specific version not listed on Omron's website - the standard relay is 180ohm and the Honda version is 120ohm coil resistance.​


The Mitsuba part seems to already be used on other Hondas. I found this link for example​


 
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#122 ·
Is the bulletin from the first post (SM-10-002-00) still current?

I took my car to a dealer today to get the A/C checked and sure enough the relay wasn't working. They replaced it, but used the Omron (G8HL-H71) part, and not the updated one listed on the first post in this thread (RELAY ASSY., POWER (MICRO ISO) (MITSUBA), 39794-SDA-A05).
 
#123 ·
Hello, im having very similar problems although when i got my AC regassed it seemed to work for a day or two, i took it back to the same garage who checked it for leaks and regassed for a second time, again the AC only worked for a short time so they kindly gave me a full refund. I have removed the air con relay as suggested in other posts and it is the offending Omron relay. I can hear a rattle from within so now thanks to Civicinfo I know I need to get the upgraded relay but would this also be the cause for the gas discharging or do i have a second fault? :confused:
 
#125 ·
Accordingly it was drained but thought this strange as he could not find any leaks on 2 different setting trying to find slow leaks also. And i have not been using AC that much. Would a broken relay be a cause for draining gas? I can contact the garage tomorrow to confirm if it was drained.
 
#126 ·
The relay would not have any effect on the refrigerant (gas) so if it was a leak then the amount of refrigerant he recovered on both occasions would be considerably less than what he charged it with so this information would be handy so we can rule this element out.
 
#127 ·
Had my relay out today as Honda claimed there was an intermit ant relay fault after the aircon service. I do have the rattle in the relay but the compressor does appear to be turning on/off as there is a definite temperature difference when operating the AC button and a change in engine tone as if there was a load over the bettery making me think the compressor is kicking in. It was more than likely the very dirty pollen filter causing the main issue for the lack of cold air getting in to the cab and the regas.
Does the AC button operate the relay to then operate the compressor? Got a lengthy journey tomorrow and worried about burning out the compressor if it's the case it's constantly on even if I'm not using the AC.

Thanks,
Gaz
 
#134 ·
my relay rattles, but when I tested it works fine.

I think a lot of people just change these relays unnecessarily. they are rated to operate from 6v to 12v, so can be easily tested by popping the terminals onto a 9v PP3 battery and checking the continuity on the switched terminals with a multimeter.

a moments work for anyone with basic knowledge of electrics.
 
#141 ·
Makes me laugh that Honda wanted £20 for fitting a relay. One minute if that to change over. Works out at £1200 per hour labour charge!!!!:eek::eek:
Mines in the auto electricians today to look at my fault. Black car, black leather and no aircon is no fun in this weather :(

Sent from my GT-I9300 using Tapatalk 2
 
#142 ·
Do feel for you mate. Black cars are a PITA. Was a scorcher yesterday. Was driving around with no filter in as mine is completely bunged up. Was comfortable at 21degrees so the regas has made a massive difference. Of to pick up new filter later today. Let us know how you get on with the auto elec.

Gaz

Sent from my GT-I9505 using Tapatalk 2
 
#144 ·
Bonus! Will get one ordered at that price ss mines getting in need of replacing if they can fix the problem. Havent checked the interior temp this week but last week it was 45 degrees in the sun when i did the diagnostic check. Have driven over 1k miles this week in these temps its not nice I tell you

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#146 ·
Well I have had to walk home from the train station. Got the bad news earlier. Its the compressor thats gone. Part has been ordered £295 +VAT. Told me he could have got a cheaper one but it wouldnt last long. He has never had a problem with the supplier he uses for this make. Total cost just over £500. Cant complain as Honda supplied one is 425 and I think plus VAT.

Sent from my GT-I9300 using Tapatalk 2
 
#151 ·
Right thx mines same dark grey oMoran , never had probs with mine I guess the water ingress is due to fuse cover not doing its job properly
 
#153 ·
I replaced the relay on my 1.8ex but no difference for me (my issue is auto climate control runs ok for warm air control but no cold air blowing through vents). But I appreciate the posts and details shared on this topic.

Extra I can add: -
- Relay cost £23 from Honda dealer.
- Use e.g. pliers or grips gently to ease the relay out
- last one in stock for the day I visited "used by garage works for job", so perhaps not an uncommon replacement.
- discussion with spares dept., suggested relay can stick closed, keeping A/C always on which can then cause pressure build up and some safety release valve enabled. This then ejects the gas etc. so in some cases relay and regas still needed.
- £72 approx. for a Honda regas and diag check of possible cause if regas not help.
 
#154 ·
Cool car again for me. Followed the appreciated suggestion here to replace relay myself, though not immediate fix for me. But regas at Honda dealer (£65) now gives correct operation. I can't say if relay change was required in my case - Honda dealer said they sometimes change relay and regas - or what made regas required (no leak detected).

Could have got regas cheaper at other garages but liked the fault diagnosis aspect included in the work and a desanitiser 'smoke bomb' is listed as being used (don't know if that's done elsewhere).
 
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