meraj90

AC stopped working back in 2015. At that time, it would work for a short period of time after a cold start. When it would not work, the compressor would not engage. Fixed this issue by adjusting the spacing between the clutch plate and compressor coil with the washer shims.

Fast forward to 2018, air conditioning suddenly stops working overnight. Compressor not engaging and also the AC cooling fan not working. The radiator fan work intermittently (which I believe is what it's supposed to do).

I've measured voltage to the compressor. I tried jumping the cooling fan with the battery to no avail. Also tried to measure power in the cable connecting TO the fan, but cannot measure any voltage. I find this a weird coincidence.

I am thoroughly confused as to what the issue can be this time around.

Thoughts?

ezone

Double check what you saw and wrote: Because BOTH radiator fans must always run at the same time. They are not wired to run independently.



Did it lose the freon? An empty system prevents the AC from running.

Is the thermal protector (on the compressor) open circuit?

meraj90

I stand by what I've said... See the video I made... I guess this concludes that condenser fan needs to be changed. Especially because I jumpered it with the battery.

But shouldn't the Radiator fan ran continuously when the AC button is on? And why isn't the compressor clutch engaging?

Link below..
https://youtu.be/zMXstBpxRkA

ezone

Only when the compressor is turned on. And when engine coolant temp requires the fans.
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The engine computer (PCM) has control over the AC clutch relay and the fan relays.

If the PCM decided the AC should not be allowed to run for whatever reason, the fans won't come on either...not until radiator coolant temp is high enough to need the fans to run.

See if the system has pressure in it, PSI should be about equal to ambient temp. At least above 50 psi to enable AC
Ohm test the thermal protector. SHould be continuity

meraj90

But the light turning on from the voltage tester (on the wire to the condenser fan), as well as the condenser fan not working while being jumpered to the batter is a clear indication it needs to be changed, no?

ezone

Oh yeah someone may tell you to just jump the wires together at the pressure switch. I can assure you that on that car doing so will make an all new very expensive problem because it will ruin the PCM.

ezone

If you run wires from battery positive and negative to fan and fan does not work, its bad.

meraj90

To OHM test the TPS can I poke holes in wires 1 and 3 and measure the resistance? I have 3 wires going to the compressor. Wire #1 (side wire) is getting 12V of current, the middle wire (Wire#2) has nothing and the other side wire (#3) also has nothing.

​​​​​​​I've read the sidewires go to the TPS and middle wire goes to the clutch. If you can confirm that would be great.

When I connect my volt light tester to side wire #1 which had 12v and ground the other end, both fans turn on and then shut off after 15 seconds. Does this help, and do you think you can explain this phenomenon?

Also, if I use my volt tester to transfer current to the middle wire will I be able to get my clutch to engage if it is in working order? It's really bugging me that I haven't been able to get it to engage.

meraj90

So I need to clear up a few basic things before going ahead with this.

I see three wires to the compressor. The Sidewire (#1) is seeing 12v when the AC is on. If I poke my voltage tester into it and ground the other end, the radiator fan and my newly replace condenser fan will both turn on for about 10 seconds. Than I'll here some noise at the relay terminal and the fans will shut off. The compressor clutch will not engage though.

Middle wire (#2) sees no voltage. And the last sidewire (#3) also doesn't see any voltage.

I've read somewhere that the sidewires are for the TPS and the the middle wire is for the clutch. Can you confirm this? I have three red wires headed to the compressor.

To test for continuity can I poke holes in both sidewires and contact my multimeter on both wires and see if it reads 0 ohms?

If I directly connect a paperclip between Wire #1 and #3, then would I be effectively bypassing the TPS, and should the AC clutch engage if the TPS was the issue?

If I use my volt light tester to send power to the middle wire by clipping the other end to the batteries positive terminal, should my AC clutch engage if it is in working order?

That darn AC clutch not engaging is getting on my nerves. I worked so hard on it 3 years back when reducing the spacing between the clutch and the coil.

I've also checked all my relays in about 4 different ways and they are all good.

Thanks for the help Ezone!

ezone

Ok I wrote this at different times and moved parts around now it's not in original order.

You can have multiple problems all at the same time.

Do not stab through wire insulation to test anything, that allows moisture to get in and corrosion can begin. In a couple short years you could have all new problems because of it.

The blower motor in the dash must work. If it does not work the HVAC control panel will disable the AC system after just a few seconds.

I THINK what you described is You provided a ground on that #1 wire, simulating the AC REQUEST signal on what you're calling #1 wire. (request signal goes from HVAC control panel on the dash, through thermal protector, to the MICU, to PCM, the PCM decides if it's ok to try it) and the system attempts to operate fans and clutch.

Your described #3 wire is supposed to become grounded (TEST THIS) when you turn on the AC button and fan in the HVAC control panel.


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Compressor harness 3 wire connector is on top of the alternator. UNplug it. Measure on the side that leads down to the compressor.


Center wire is for the clutch field coil. Measure resistance between that center terminal and ground, I expect 3-4 ohm.
If you provide 12v+ to the center terminal the clutch should click as it engages. Does it?
In the picture above, that field coil measured over 12K ohms. It is bad.
The two outer wires are for the thermal protector. It should show continuity (zero ohms)
If open circuit, these two outer wires can be jumpered together (for test purposes)
If continuity is found, it's ok. Reconnect and check something else.

meraj90

Thanks for the walk through Ezone. Based on my tests, it looks like I'll need a new compressor.

No continuity across the two wires to/from the TPS. When I jumper them, my radiator fan and condenser fan turns on but compressor doesn't engage. Also no resistance being measured across the coil (ie infinity).

I'm inclined to just change out the whole compressor at this point as opposed to the TPS and Clutch. Any comments here?

The downside to replacing the compressor is having to remove the freon and recharging the system. Also need to purchase a vacuum pump and a manifold set. I called around for rentals on the vacuum pump here but had no luck.

But I feel as though the clutch and TPS will be a pain. In particular getting the bearing off and just accessing the location of the TPS with the low and high pressure lines still connected. Anybody with experience have some advice?

ezone

It's kinda unusual that both items (clutch coil and thermal protector) would go out at the same time, in my mind it is possible the compressor took a poop and overheated. I probably would want to pull the refrigerant out just to open up the lines and have a look for evidence of internal failure (gray or black coating inside the discharge line and port, metal in the drier filter screen, etc)

Rotate the hub of the clutch to make sure the compressor isn't locked up--- and make sure it feels like it is turning something inside the compressor. (it should rotate but with some resistance)





My preference is always to keep an original compressor working as long as possible, because that's the most reliable unit the car will ever have IMO. Honda sells all of the external parts for the original compressors, and I can replace the clutch/pulley/coil without unbolting the unit from the engine or messing with the freon, There's a thread somewhere in this forum with some pics of it done in this body style

Aftermarket compressors are a crapshoot, and from what I've seen original clutch and coil parts from Honda don't fit the aftermarket compressors when they fail. Just the fact I have had to find this out should tell you they aren't always great.
Aftermarket compressor will always make you buy a filter/drier (maybe more) or you won't get any warranty on it.

meraj90

So it's been almost a year, still no AC - here is what I've done so far.

Replaced the coil and thermal protector set on the AC compressor.

Verified there are no leaks in my system.

I believe there is an issue with the wires that connect to the compressor harness (on the alternator side). When pressure is applied the connection while AC is turned on, both fans turn on, now the compressor engages, HOWEVER, the same problem exists as before, the system runs for maybe 15 seconds but then a relay is triggered and it turns off.

I plan on fixing the wiring issue, but for the life of me I can't figure out why the ECM/ PCM is cutting power to the AC system (fans turn off and compressor disengages)

Is the ECM/PCM the issue?
Do I need to change the refrigerant pressure switch?

Please help

meraj90

Bump

ezone

Sounds like poor contact among the three pairs of terminals inside that connector shell, maybe one of the female terminals have been spread or lost tension and no longer grips the male blades tightly



I'd guess the system is overcharged, but would need to confirm actual system pressures when this happens.
Compressor and fans kick off when the high side pressure is too high, probably well over 400 PSI when it shuts off.