1990 Honda Civic A/C compressor won't engage

AJHALDISJR

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

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 2 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.

2 Replies

KHLOW2008

MECHANIC
41,815 POSTS

Hi ajhaldisjr,

Please use the reply to question link to post for any unfinished subject so that the person who attended to you can follow up when notification is received.

Was this

answer

helpful?

Yes

No

Monday, July 14th, 2008 AT 1:27 PM

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.