My 96 EX V6 AC intermittently works. Sometimes blows cold air & later on same short trip will blow hot for awhile or for the rest of the trip. When blowing hot air, the condensor fan is running but the compressor is not running. I checked the refrigerant level & pressure & it is fine. The intermittent nature of this makes it tough to troubleshoot. I think I have this narrowed down to either the compressor clutch relay (most likely culprit) or a bad pressure switch. If my pressure switch is bad, would the condensor fan run & the compressor not run? In case it is the pressure switch, does the system need to be evacuated to replace the pressure switch? I'm thinking probably yes. Can someone tell if the condensor fan should only run when the compressor runs? If so, then if condensor fan runs & compressor is not running then my next step is to troubleshoot/replace the compressor clutch relay which has been my chief suspect all along. Appreciate any knowledgeable feedback out there. Thanks.

 

Ok, you are off to a good start. I would pull the one wire plug going to the compressor when the compressor is not working. Check that it has 12V when the A/C is turned on.

 

If my pressure switch is bad, would the condensor fan run & the compressor not run?
No, pressure switch disables ground to cooling fans.

In case it is the pressure switch, does the system need to be evacuated to replace the pressure switch?
Yes, there is no isolation valve or check valve.

Can someone tell if the condensor fan should only run when the compressor runs?
Both cooling fans should run whenever compressor is engaged and whenever cooling is commanded by coolant thermoswitch A.

One other possibility is excessive clutch gap, preventing clutch engagement when commanded. Try rapping the compressor face w/ a hefty stick when AC is inop and see if clutch engages immediately. If yes, the clutch gap needs to be reduced by removing a shim from beneath the clutch plate.

good luck

 

the compressor clutch gap is too big, pull off the compressor clutch disk and throw away a couple of the thin shim washers.
You can prove this problem with a Caveman test [sm=bounceybounce.gif];
When the A/C is on, cooling fans running and compressor not.
Reach down there with a long pry bar and smack the clutch toward the compressor.

 

Thanks all for the excellent advice. I will check the 12 V at the compressor plug & also the clutch gap. I understand a relay can fail intermittently but I guess I'm surprised that clutch gap would cause an intermittent problem like mine. I would expect slippage & possibly poor cooling even when running & I've not seen either. By the way, I hang around probably 5-6 Honda forums but my initial experience with this one is excellent - much better than the others in terms of timeliness & quality of responses. Since I have 2 older Accords (used to be 3) I'm sure I'll be here quite a bit. Thanks again.

 

Update: I took TexasHonda & Hondadude's advice & checked the red clutch/coil lead in "failed" mode & I still had battery voltage which proves my relay is fine. I then forced the clutch against the rotating pressure plate (exciting - I recommend a thin wooden stick/pole - less sparks than metal) & lo & behold, it engaged. The gap is out of spec - not by a huge amount but it is bigger than the outside tolerance. I guess that over time the natural progression is for everything to wear & loosen to a wider gap.
So, it seems clear I need to pull the clutch & remove some shims. I've never messed with a compressor clutch & there is precious little clearance from the end of the clutch to the inner fender - maybe 3/4". I'm not sure what I'm getting into here. I don't think there is enough clearance without pulling the compressor & then I'm not sure you could do it without evacuating the system? Can you do this with the compressor in place or must it be removed? I'm wondering if I might be better off to take it to a reliable mechanic & have them do this. I wouldn't expect there to be too much to it for them....maybe 1 hour labor or something like that? Any opinions or experience on this? Thanks again.

 

Yes, it is possible to remove the shims w/o discharging the system. Here's what I did.

1) Disconnect battery negative cable (very important!) and remove the alternator.
2) Remove the PS pump, pressure hoses and swing out of way. You will need to disconnect and plug return hose to reservoir (maybe supply also, but I think not). Some loss of PS fluid inevitable.
3)Remove AC compressor mounting bolts and reposition slightly towards center of engine and tip clutch face upwards for access. You may need to release some AC hosesupports for flexibilty.
4) Measure clutch gap. It should be 30-40 thousands of inch (mils) but measure several times on opposite sides (clutch may not be parallel). Average opposite sides. The avg. specified gap is 20 +/- 6 mils but check specs on your compressor and accord model.
4) Remove single 10mm nut retaining clutch plate. A restraint tool (check auto parts store for loaners) or other arrangement is necessary to restrain the clutch plate from turning. Impact ratchet or wrench would also work. Nut is not tight.
5) Carefully pry the clutch plate loose w/ a couple of flat blade screwdrivers on opposite sides. It comes out easily.
6) Lift clutch plate. The shims will likely stick to the clutch plate, so watch out they don't drop out.
7) Remove the shim that will return you to spec, probably thinnest shim. You may need to purchase a shim to get in spec.

Reverse compressor removal to reinstall.

good luck

 

Thanks for the helpful info. I have a V6 which means the engine layout is different so I still may be able to do this without removing & evacuating the compressor but the procedure will differ - maybe easier as I don't have to remove the alternator & PS pump I don't believe.
Just for grins, I measured the clutch coil resistance. What a shame if I corrected the air gap but found out later I have a weak clutch coil that should be replaced. If I did it right, I got right at 1 ohm. I have a 96 Accord 4 cyl shop manual that I've been using (had a 96 LX 4 cyl as well until last year) & I've been assuming that the A/C was the same between the V6 & 4 cyl engines. Now, I don't think so sure as I've found some clear differences. My manual tells me the coil should measure 3.6 +- .2 ohms.
I'm hoping someone on this forum can tell me what should the resistance be for a 96 EX V6 clutch coil & how/where to measure it?
In case I find out that I also need a new coil & I decide to take it on, my next question is how easy is it to do this & would a sane person take it on without removing (benching) the compressor? Does the pressure plate, pulley & coil all come off easily without a special puller & then the need to press it back on? Thanks.

 

What kind of multi-meter did you use? Less than about5 ohms is difficult for an inexpensive meter to have any accuracy.

 

Good point. I had actually forgotten to zero out the meter before I tested. I'm using 2 different Radio Shack Micronta meters & 1 gives me just below 3 ohms & the other gives me about 3.3 ohms - both zero'd out as best I can. This may be a dumb question but if a coil is failing, as in getting weaker, would the resistance be expected to go up or down? Thanks again.