'90 civic A/C problem - help needed!

90 Civic 3 door hatchback with 1.5 engine:

Car has obvious factory wiring, but the A/C relays in the car (2 of them)
are *not* the relays that all the parts suppliers (even the dealership) are
showing in their parts list. And, they can't seem to match 'em up!

The relays in the car are square, 5-pin relays (although the center pin
doesn't connect to anything, as the harness plug doesn't have a wire
connected to the center slot).

The replacement relay, according to the books, is supposed to be a 4-pin,
long rectangular relay -- but the pins are oriented in a different direction
and won't plug in to the sockets in the car.

On the 5-pin relays, the top and center pins are horizontal, while the left,
right, and bottom pins are vertical. (If I recall, the 4-pin ones that they
showed us at the auto parts store were top & bottom horizontal, and left &
right vertical).

Anyway, can anyone solve this mystery for us? The only info on the 5-pin
relays are two numbers: 74987, and 9413, and it says "Assembled in the
Dominican Republic". These don't match up to anything in any of the
suppliers' info. I've looked on the net as well -- no luck finding a match.
All those sources also indicate the 4-pin relay, which won't work.

ANY info appreciated!! Thanks......

 

On many Hondas, A/C is a dealer installed option. When my girlfriend in
college bought a Civic back in '87, the dealer decided to put in an
after-market A/C rather than a OEM Honda unit. Perhaps this is what
happened to your '90 Civic as well, and that this is the reason the
relays don't seem to match what the parts list says.

The 4 and 5 pin relays you describe are standard automotive relays. If
you look carefully at the bottom of the relay, you might find terminal
numbers next to the pins:

Top, horizontal: 87, normally open (NO)
Center, horizontal: 87a, normally closed (NC)
Bottom, vertical: 30, Common
Right, vertical: 85, coil
Left, vertical: 85, coil


On the 4 pin standard (non-Honda) relay the 87a (NC) terminal is
missing, all the other terminals are there and has the same orientation
as on the 5 pin model. You can safely use the standard, 4 pin relay they
showed you at the auto parts store.

 

Thanks for the info, but the pin configuration is different on the
store/dealership relays, so they won't plug in to the sockets.

Do you have any idea what the amperage/wattage is supposed to be for these
relays? I found some online but they're either 70amp/800watt, or
30amp/350watt. Both will fit, but I don't want to put the wrong ones in and
maybe burn up something! Thanks....

 

You can safely go with the lower rating (there is probably a 15A or 20A
fuse in the circuit). I bought some from http://www.partsexpress.com,
part number 330-070 (http://tinyurl.com/yux6z). They have an even
cheaper, off-brand version as well, part number 330-073
(http://tinyurl.com/34457).

These types of relays are very common, so if you bring the one you have
to the auto parts store they will probably have at least a 4 pin type
that will fit your socket. The most common rating is 30A, sometimes you
can find 40A. Either one will work.