Automotive Air Conditioning Information Forum

Hi All, I'm new to the forum and a beginner DIYer.

I'm having issues with my Cars air conditioning system.

The AC condenser fan was not working originally,and I thought a simple replacement would do the trick,but of coursemy life could never be this easy.

When the AC button is on, neither the radiator fan or condenser fan works and the compressor clutch is not engaging. The radiator fan is still being activated when the temperature of the engine is hot enough, and now that I have replaced the Condenser Fan, with the AC button fan on, both fans will turn on intermittently when activated by the engine temperature.

I have checked all the relays manually, they are good. The wiring to my fans are obviously good, per my experiences above.

Regarding my Condenser clutch is not engaging...

I've used a voltage tester and poked one end in the wire to the compressor and grounded the other side. When I do this, both condenser and radiator fans turn on, but this only happens for 10 seconds before both fans shut off. This only happens immediately after I press the AC button after a cold start.

I've tried using the same voltage test light to poke into the wire to the clutch and supply power to it by connecting the other end to the positive terminal on my battery. I do not see the clutch engaging.

Where do I go from here? Should I troubleshoot the pressure switch, thermal protector, compressor clutch plate? Any input would be truly appreciated. I havent check for pressure in the lines yet as well. Don't know how beneficial this really is without the compressor running.

Sidenote: 3 years ago my AC stopped working. Compressor clutch plate was not engaging. I adjusted the spacing between the clutch plate and the coil with washer shims and it began engaging with the coil again...

Help please!!!

Maybe the diode in the clutch harness on the compressor or the TPS (thermal protection switch) mounted at the rear side if the compressor housing has failed open due to reverse polarity or a negative voltage disengagement spike or back EMF from fan problems.
The TPS is intended to disengage the clutch and reset automatically when fans fail to keep discharge pressures reasonable.
hotrodac

ice-n-tropics wrote:Maybe the diode in the clutch harness on the compressor or the TPS (thermal protection switch) mounted at the rear side if the compressor housing has failed open due to reverse polarity or a negative voltage disengagement spike or back EMF from fan problems.
The TPS is intended to disengage the clutch and reset automatically when fans fail to keep discharge pressures reasonable.
hotrodac

Thank you so much for the reply. I guess the next step would be to test the thermal protector switch and the diode in the clutch. Any documentation or instructions on how to test these?

Once again, thanks for the tips!

I'd completely unrap the harness cover including the heat shrink tube around the diode and check the diode and wire accidental contact per common trouble shooting practice.
The diode is rated at 600 v (or better 800 volt) usually Motorola branded.
Arching of the battery terminals or arc welding without disconnection the battery or fan electrical generation during fan rpm deceleration without relay isolation can blow the diode. Also, clutch abnormal rapid instantaneous disengagement can generate a negative voltage spike over 600 volts and cause diode failure. The diode in the compressor harness stops clutch field coil stored energy collapse after disengagement from sending negative voltage spikes and infecting computer electronics.
hotrodac

Thanks for the response.

I've figured that the middle wire in my 3 with harness is going to the clutch. I don't measure any power going to this line unfortunately. When I put power to this line, the clutch still does not engage. One of the side wires is seeing 12 volts (I believe this is to the TPS). The other sidewire (which I believe is the ground) does not measure any voltage. I tried checking for continuity between the assumed TPS wires and I don't measure anything ...

I've also tried to measure continuity from the middle wire to the compressor body and don't measure anything.

Now either I am doing something wrong or both the TPS and diode/clutch needs to be replaced.

If I am being cheap can I just replace both (clutch and TPS) and get away with keeping the compressors body?

I potentially have access to a car hoist for $20/hr. How feasible is it to do this repair and avoid draining the freon lines? I guess it'll depend on how stuck on the bearing is by the clutch, and if a small puller can fit in. Might need to unbolt the compressor a bit to turn it so that the puller doesn't interfere with the passenger wheel/body of the car... Also will access from below suffice if I have a hoist or do I need to remove the alternator to have access from above....

Thinking of taking a trip to my local autowreckers and grabbing these parts this weekend hopefully.

The extra 3d wire on Hondas is a signal for the computer to know when the clutch is engaged.
hotrodac

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

Bump

Maybe the compressor clutch gap is too large once warmed up. Think that was a common issue on Hondas of that era.

atikovi wrote:Maybe the compressor clutch gap is too large once warmed up. Think that was a common issue on Hondas of that era.

Thanks for the reply but doubt it. Coil is brand new and it disengages within 10 seconds. I actually went through that issue three years ago and was able to solve it by adjusting the gap. Also, power cuts out to the whole AC system (fans turn off).