1990 Honda Civic Compressor not engaging

Hi ajhaldisjr,

There is a relay and it is located just behind the front left headight near the radiator, 2 of them, 1 for fan and the other compressor.

Ok, well thanks so much for the info regarding the relay. It was actually bolted to the side of the fan housing, and controls both the fan and the compressor. I do want to be sure that it is the problem before replacing it, however.

With the harness connector (to the relay) disconnected, I see no voltage on any of the 4 harness wires feeding the relay (I assume that at least 1 should be 'hot' with the a/c switched on). With the relay connected, there is no voltage going to either the fan or the compressor (expected). The fan works when jumped directly from the battery. This all seems to indicate (to me, at least) that the realy may be ok and that something further upstream is the problem.

Again, I have already (again) checked all fuses, replaced (apparently unecessarily) the a/c switch, verified the function of the fan and compressor, as well as the system charge.

Is there a temp sensor, or some other control in this loop that I still haven't checked? And if so, where is it located? Thanks again for your help so far.

Hi ajhaldisjr,

There should be 1 powered point at all times, it gets its power from the battery via the underhood fuse box, there is a fuse there. White colored wire.

When AC is turned on, there should be 2 powered points on the relay socket. The second gets its power from the underdash fuse box. Black/Yellow.

Since both wires are not getting any power, there should be a open circuit.

Check the connector near the battery, ie RH fender inside near the ground wire. It could be contaminated.