04 gx470 ac woes (1 Viewer)

[Augustiron]

Hi Mud crew,

So we got a 97k mile gx470 non nav in the fall and all seemed well, but now that the temps have finally warmed up in the sierra, I found the AC doesn't work and the better half is not pleased.

Looking for advice/experience.
here is what I know:

- compressor clutch engages for 3 seconds then disconnects when ac turned on.
- Clutch stays when magnetic relay is removed and jumpered, seems to blow cold (it was a cool day so hard to say, will retest.
- replaced magnetic relay with new oreilley part, same results as old relay.
- Tested low side pressure while jumpered, was nearly empty, put a couple of cans of DIY oreilley AC refill crap in to get it up to 35 psi.
- still blows warm, ac light flashing.
- tried different combos of auto/manual/max cool, still blinking and blowing warm.
- pulled AC codes got 21 (solar sensor) and 24 (magnetic compressor clutch relay) in a dark garage with the new relay in place.

So, compressor seems to work when jumpered, meaning it and the wires to it are OK (did the timing belt last month).
System has pressure (now)

I only have a basic OBD scan tool that really only reads emissions codes, but otherwise am a pretty competent DIY wrench.

What else can I do short of taking it to a shop or just shooting in the dark and replacing the compressor?
I also tried a known good relay out of a friend's 470 and had the same results as my original and the new oreilley one, so I am ruling out the relay even with code 24, can anything else toss code 24?

I also disconnect the battery for a while when the relay was replaced out of caution and the advice in another thread on the internet.

Thanks in advance.

The sooner I get this fixed, the sooner I can work on cars that are supposed to need work, like the 2 fj40s, fj46 and fzj80 turbo diesel/manual conversion I am currently working on.

 

[Augustiron]

Also, is there real harm to be done leaving the jumper in place all the time instead of the relay?
I understand the compressor will see more wear, and gas mileage will take a hit, but how bad would it be?
Thx

 

[CarolinaGX]

could it be a temp sensor? I have no idea, just trying to think of possibilities.

 

[GldMembrGx]

I just found a 100 series rear T badge, that match up with the two the holes?

 

[Augustiron]

I was thinking perhaps the cabin temp sensor was bad, but that would only affect auto mode I would guess. Manual mode should still blast cold, correct?

 

[Augustiron]

So here is what happened for anyone else that may be reading this looking for answers to a similar situation...

The compressor clutch speed sensor wire broke off from the 3 wire plug connection and was causing the fault.
I'm sure I did this myself when I had to move those connectors and the compressor when I did the timing belt job last month.
The wire was not externally visibly broken, but i took it to a shop and they hooked it up and ran the diagnostic that pointed to the speed sensor, he pulled on the 2 wires out of the back of the compressor and one came out of the little rubber grommet in the back of the plug.
I had looked down there and unplugged and replugged that 3 wire plug when diagnosing myself but missed the broken wire.
He said they could only replace the compressor as the wire and connector are hard wired, to the tune of about $1500 for the total job.

I figured last resort I can bypass the connector plug and connect the broken wire to the wire it needed to connect to one of several external ways.

But first I tried to fix it right.

I was able to pull the disconnected pin out of the plug (thanks for the advice Ofer!), strip back the wire and solder them back together with decent access through the wheelwell with the rubber fender inner splash guard removed.

10pm cool night test shows no more blinking AC light and it's blowing cold air. I'll test again and test low side system pressure when it's hot out.

 

[Augustiron]

I should also mention the mechanic cringed when I told him that I jumpered the relay to diagnose it.

He said the relay is a failsafe to protect the system if there are other problems like too low pressure, too high pressure, etc.
He advised not to do that.
Ymmv