Community Forums

Switchflicke · 06-19-2017, 12:04 PM

The dash air stopped working after a couple of months of being parked. The compressor will not engage so I had the refrigerant checked and it was all OK. I bypassed the pressure switches for testing and that seems OK. No voltage at the compressor clutch, but if I 'inject' 12v at the relay the volts shows up at the clutch so it looks like the wiring is OK from relay to clutch. What I think I should now do before anything else is to look at a diagram of how the power gets to the compressor clutch.

I read this forum almost everyday and I learn so much from the problems of others!!

Thanks in advance to those who might put me on the right track

Stan

gseason · 06-19-2017, 06:29 PM

Attached is the wiring diagram from a 2004 Allegro W22 chassis. Hopefully it is close to the same as yours.

Switchflicke · 06-20-2017, 07:11 AM

Thanks George.

The diagram has lots of good info but on my machine, there is a switch on the low side and the high side. I understand that, but also a switch on the compressor itself. What would that one be for? Last night I took the relay out and jumpered it. The A/C worked like a champ. What's the danger of just leaving the jumper in for the summer?

Tom N · 06-20-2017, 03:43 PM

-Tom, W3TLN

Switchflicke · 06-20-2017, 04:56 PM

That looks good Tom, and I will use that when I finally get around to figuring why the blower won't keep working on the second from the highest selection. What I'm trying to follow now is the power from the A/C rotary switch through all the cut-offs to the compressor clutch. I'm sure there is some Workhorse magic involved too.
Stan

Switchflicke · 06-22-2017, 07:23 PM

The diagram idea isn't working for me.

Has anyone on the forum had an air conditioner problem similar to the one I posted above. I'm at my wit's end trying to get it going without taking it to a shop. Maybe I'm too cheap with the dollars but isn't that one of the reasons we read and submit on this forum?

Any help/input will be much appreciated.

Tom N · 06-22-2017, 07:37 PM

Switchflicke · 06-23-2017, 05:53 AM

Thanks Tom. My problem is the compressor clutch won't engage. When I force it to by jumper the relay, the Air works great. So what I'm trying to figure out is why there is no power going to the clutch.

AKIQPilot · 06-23-2017, 06:48 PM

Quote:

Originally Posted by Switchflicke

Thanks Tom. My problem is the compressor clutch won't engage. When I force it to by jumper the relay, the Air works great. So what I'm trying to figure out is why there is no power going to the clutch.

Maybe I'm misunderstanding but if you jump the relay and the AC works fine then your problem is either the relay or something between the selector switch and the relay, not between the relay and the clutch.

I assume you've tried to change out the relay with one that you know to be good? Have you traced and verified you have the proper signal to the relay coming from the switch.

I assume when you say you jump the relay yo mean you go directly from the hot lead in to the relay to the lead going out to the clutch?

CJ7365 · 06-23-2017, 06:59 PM

OK, I am no expert, and not saying this is your problem, but this is what I encountered.

My A/C worked before I did the following.

I ordered the Engine ECM upgrade from Ultra RV, once installed my A/C compressor would not engage.

Because I did this right before the summer, I just assumed my refrigerant was low, it was not, and I could engage the A/C compressor with a 12v source.

I called Jon from Ultra RV, and he told me it was possible it was the ECM. So he sent me a new one out ASAP and a return label for the installed ECM.

Installed new ECM and my compressor worked.

I cannot remember if Jon had stated that the power to the A/C relay comes from the ECM.

My be worth a call to Ultra RV and ask them, they are the experts and have great customer support.

I have been running the new upgraded ECM for over a year now, 7000 miles.

So with my experience, I would say that the ECM sends a signal for the A/C compressor.

Hope this helps

Switchflicke · 06-23-2017, 07:40 PM

Thanks for your reply CJ7365
I also have had excellent dealings with Jon regarding my Actica instrument panel display.
My son who is a Mister Goodwrench told me that the PCM supplies grounds for all sorts of stuff associated with the installation, and with a special code reader I should be able to see an A/C code. Well my code reader is just a common one (ScanGageII) so it didn't show any code but I hit the reset button anyway. The compressor engaged properly and everything got real cold real fast. Tried it a half a dozen times and always worked. Maybe the PCM got a warning to shut the A/C down for what ever reason??

Anyhoo now it works. I'm happy and not too much lighter in the pocket book

Stan

CJ7365 · 06-23-2017, 08:16 PM

Quote:

Originally Posted by Switchflicke

Thanks for your reply CJ7365
I also have had excellent dealings with Jon regarding my Actica instrument panel display.
My son who is a Mister Goodwrench told me that the PCM supplies grounds for all sorts of stuff associated with the installation, and with a special code reader I should be able to see an A/C code. Well my code reader is just a common one (ScanGageII) so it didn't show any code but I hit the reset button anyway. The compressor engaged properly and everything got real cold real fast. Tried it a half a dozen times and always worked. Maybe the PCM got a warning to shut the A/C down for what ever reason??

Anyhoo now it works. I'm happy and not too much lighter in the pocket book

Stan

Well glad you got it working and are keeping cool now.