2009 Jk Aircon issue

[Milsy]

Hi all,

I have googled however couldn't find anything yet.

My AC intermittently switches on and off, regardless of where the switch is Windscreen/feet/face etc, regardless of cold or hot setting.

The AC button itself is unresponsive also, doing it's own thing.

I replaced the HVAC console, thinking that it had shorted out. It had lost the lower LED lighting so assumed that this was the case.

I have disconnected the AC switch next to the compressor on the high side until I can find a fix so that the AC doesn't actually switch on even though the switch is telling it to.

Thoughts?

I have found nothing on the US sites, so it's bizarre!

Cheers!

[Banshee]

Sounds a bit like spurious signal to the ECU telling it to turn on/off. So the first question becomes, "Have you tried turning it off & on again?"

You Tube

No, seriously. Stop laughing.

Have you disconnected the battery & left it for half an hour or so for all capacitors in the various computers to discharge? This resets all the variables stored in volatile memory in the computers that control everything. It can also remove corrupted data that might be causing the computer to toggle the A/C.

it is the quickest, easiest, and cheapest step in troubleshooting many problems. If you have, or do, and it doesn't fix it, then you are getting to the realm of hardware problems. Wiring or computer issue. But since it is no longer a simple on/off switch & all done through data busses by computers, I'd be suspecting a computer issue that may need to be fixed professionally, at, (probably), great expense. Hope I'm wrong on that, though, and there may be someone else with better ideas, yet.

[Milsy]

Originally Posted by Banshee

Sounds a bit like spurious signal to the ECU telling it to turn on/off. So the first question becomes, "Have you tried turning it off & on again?"
https://www.youtube.com/watch?v=nn2FB1P_Mn8
No, seriously. Stop laughing.

Have you disconnected the battery & left it for half an hour or so for all capacitors in the various computers to discharge? This resets all the variables stored in volatile memory in the computers that control everything. It can also remove corrupted data that might be causing the computer to toggle the A/C.

it is the quickest, easiest, and cheapest step in troubleshooting many problems. If you have, or do, and it doesn't fix it, then you are getting to the realm of hardware problems. Wiring or computer issue. But since it is no longer a simple on/off switch & all done through data busses by computers, I'd be suspecting a computer issue that may need to be fixed professionally, at, (probably), great expense. Hope I'm wrong on that, though, and there may be someone else with better ideas, yet.

Ah yes, the on/off trick. I do it with everything else, not sure why I didnt do this. I'll try tonight to see how it goes.

Thanks!

[Milsy]

Unfortunately that didn’t work.

I tired a few different googled methods off resetting the ECU too.

Anyone else? Surely this can’t have happened to just me?

[timbotrog]

Several years ago now I had an almost identical issue come into the work shop.

A/C not working including after changing the control panel over twice before it got to us.

You are not going to believe this, and I wouldn't if i didn't see it with my own eyes, but the problem turned out to be the dashboard.

The dash cluster works as a kind of "full stop" in a sentence and Jeep, in their infinite wisdom, have these things wired so that the signal for the A/C runs through the dash cluster. The was a break in the wiring in the cluster and it effectively didn't know to turn on.

We swapped the cluster over for a known working unit and it worked perfectly.

The bloke got a 2nd hand cluster for a couple hundred from a Jeep wreckers and hasn't had a problem with it since.

Find someone with a JK the same year as yours and swap the cluster over, it's only a 5 minute job to do.

[Milsy]

Originally Posted by timbotrog

Several years ago now I had an almost identical issue come into the work shop.

A/C not working including after changing the control panel over twice before it got to us.

You are not going to believe this, and I wouldn't if i didn't see it with my own eyes, but the problem turned out to be the dashboard.

The dash cluster works as a kind of "full stop" in a sentence and Jeep, in their infinite wisdom, have these things wired so that the signal for the A/C runs through the dash cluster. The was a break in the wiring in the cluster and it effectively didn't know to turn on.

We swapped the cluster over for a known working unit and it worked perfectly.

The bloke got a 2nd hand cluster for a couple hundred from a Jeep wreckers and hasn't had a problem with it since.

Find someone with a JK the same year as yours and swap the cluster over, it's only a 5 minute job to do.

Haha, no way! I’ll get it checked out. Will Jeep or a auto sparky be able to identify the cluster being buggered?

[st_za]

Have you checked that it's still fully gassed up?