Outer Limits 4x4 Board

I drove thru a deepish mud hole a few weeks back and the air con stopped working.

I've pressured washed the condenser and radiator and there is no overheating problem.

When I press the air con switch the RPM rises slightly. I assume it's the ECU compensating for the additional load. The air con switch does light as well. I only get warm air out so at least the blower motor still works.

I've checked the fuses/relays and cooling fan - continuity and 12V test. The ralays and fan work with 12V applied directly.

The inlet and outlet lines to the compressor are both warm when the air con is on.

I was suspecting a leak because maybe the cooling fan pushed into the condenser cauing a leak but I've just checked the the gas level by pressing in the valve in the air con cap (thanks PJ.Zook for the tip in the other air con thread). I do get gas coming out but it's not cold at all, it's like air coming out of the tyres. The sight glass is clear with the air con either on or off.

I'm now thinking it's something electrical but don't know what else it could be???????

Are there anmy other things to check?

You could check the depth of your next "mud hole"

is the compressor clutch engaging? maybe the compressor isn't turning for some reason

Compressor and/or compressor wiring is where I'd be starting too.

Just get someone to switch the air on & off whilst you look under the engine bay. If the compressor doesn't kick in, check the wiring plug isn't either detached, or full of said mud hole still.

If that all checks out ok, then I'd be going for the pressure switch, which should be near the drier unit inline. Just short out the two pins there, thus simulating full pressure and see if it fires up then. If it does, you need to get it checked out as you either have a leak, or its just a big co-incidence that it stuffed up (gotto a low enough pressure) right at the same time that you went through the mud hole.

Stranger things have happened...

How do you know if the compressor is working. I had a look and everything is spinning all the time. I can't see if the clutch is engaged or not.

8 wrote:How do you know if the compressor is working. I had a look and everything is spinning all the time. I can't see if the clutch is engaged or not.

Your belt will spin the compressor pulley all the time but if you look at the front of the compressor you will see it is not turning when AC is off. Switching AC on should engage the clutch and you'll see the front of the compressor turning.

Those 6 flat rivets at the front should be spinning around and around and around when engaged.

Just a simple thing, but you said you pressure washed your condensor and radiator. You didnt by any chance bend all the fins over on the condensor during the pressure washing did you?

Not sure if you did, but i've seen the radiator of a toyota bobcat ruined by over zealous use of a water blaster...

Just a thought...

Yep as others have said i would be checking to see if the clutch is engaging on the compressor.
As for you checking to see if escaping gas is cold, it propably wont be cold if it was just the vapourised gas coming out, but when the liquified gas starts spurting out, thats the bad shit that can cold burn you. Thats basically how aircon works, it utilises the cooling properties of a liquid turning into a gas, which is what it does when released into atmosphere, or in the internal aircon systems case, when it passes through a restriction.

I would have to second the notion about the condensor unit being damaged by the pressure washer.

It seems from what you have described regarding the amount of gas in the system that that isn't the problem (although you could look in the top of the drier unit to see if the glass is clear or not to prove this).

Its highly likely that the condensor is blocked and/or stuffed from the pressure washing.

... or of course the compressor as previously mentioned

I just had a look and the compressor clutch isn't engaging with the A/C on.

Where can mud stop the clutch engaging? Is that a common occurance? Could it be as simple as sticking a hose up to the front of the compressor to flush out any dirt?

Had a look at the connections and they're all still connected. I might have a closer inspection at the connector though to make sure there's no dirt stuck on there.

Also, what tells the clutch to engage? Is it a signal from the ECU, pressure switch????

I don't think pressure washing the condenser was the problem as I wasn't that aggressive with the washer. Plus I can't see any bent fins.

If it's only the thermostat in the fanbox signalling the compressor, that shouldn't be a problem due to mud etc should it?

So the problem is likely to be the compressor itself not the signal to the compresser???

With the aircon on, just disconnect the wire at the compressor and see if there is 12volts there. If there is then theres something propably wrong with the compressor clutch, which you can change reasonably easily if you have a puller. If there isnt 12volts then there could be something wrong elsewhere down the line, start tracing the wire if you can. Test the pressure switch and see if it has continuity.