1990 Honda Civic Compressor not engaging

AJHALDISJR

MEMBER
1990 HONDA CIVIC
4 CYL
FWD
AUTOMATIC
173,000 MILES

Hello and thank you. My daughter's civic a/c compressor clutch does not engage. If I jump it directly from the battery, it engages / disengages as it should. I have checked all of the fuses and replaced the a/c on / off switch. I assume that there is a relay that cicles the compressor on and off. Where is it located? Any other suggestions?

3 Replies

KHLOW2008

MECHANIC
41,815 POSTS

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.

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Sunday, July 13th, 2008 AT 2:10 AM

AJHALDISJR

MEMBER
6 POSTS

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.