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
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