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Old 04 Aug 2004, 02:16 am
Randolph
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Default Re: 94 Civic AC switch pinout?


remove wrote:

> relay...doesn't. I don't have a wiring diagram, Is there anything
> between the coil ground pin of the relay and the switch on the
> instrument panel?


Yes. The relay coil ground pin is connected to the ECU. When the ECU
gets a request for A/C, it will delay turning on the relay while it
enriches the air/fuel mixture a bit. The A/C request comes to the ECU
through the A/C pressure switch, the A/C thermostat at the evaporator,
the A/C main switch and the ventilation fan switch.

> Isuspect the switch. If I had the pinout for the
> switch I can troubleshoot from there. Can anyone provide this
> information? IIRC there are 5 pins on the switch.


That's a lot of pins, don't recall it having that many. Are you sure
this is an OEM Honda A/C? I once had a Civic where the dealer had
installed an after-market A/C.

> I've got 1 pin with
> switched power and 1 ground for sure. I imagine 1 is for the
> illumination of the switch. That leaves 2 unknown terminals.Any input
> would be appreciated.
> Thanks, Tom


You can find the wiring diagram at
http://www.honda.co.uk/owner/civicmanual/pdf/22-6.pdf. This wiring
diagram is for the European Civic, but it is identical to the US version
with three minor exceptions:

1. Ground for the condenser fan goes to ground location G751 (EU: 701)

2. Thermal protector for the compressor is shown as a separate item in
the above referenced schematic. In the US schematic it is not shown, but
it is still installed in the car (internal to the compressor)

3. The A/C on indicator in the EU schematic is shown as a simple light
bulb. In the US variety it is shown as an LED connected through a
dimming circuit.

I have compared the above referenced .pdf with the wiring diagram in the
Helm manual for my '94 Civic, and find only the above mentioned
discrepancies. Wire colors, fuse numbers and ratings etc. match.

A couple of trouble shooting tips: If the A/C-on indicator does not turn
on, the problem is in the A/C main switch, or, more likely, in the
ventilation fan switch.

If the condenser fan comes on but the compressor does not, the most
likely problem is the A/C pressure switch. It could be a faulty pressure
switch, or improper pressure in the system. I do not know if this is a
high pressure lockout or a low pressure lockout. I have seen both on
various cars.
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