A/C help.

julian · Post by **julian** » Sun Aug 19, 2007 4:23 pm

Hi guys.
Went to switch my A/C on this morning and nothing happened... Fan on, AC switch light on, but no click from an engaging compressor.
Compressor was changed January 07, and regasssed shortly after. Was running well for the last weeks of hot summer and I have only been switching it on periodically as advised by auto electrician.
I have recently installed a new car stereo in the dash and it is possible that a connection was severed accidently but nothing I can see.
My under-dash fuse box doesn't have a listed fuse for AC, should it?
I don't have experience with A/C so not sure of what I should be looking for with my multimeter.
Any advice on where/what to look for?

Thanks

timmo · Post by **timmo** » Sun Aug 19, 2007 6:01 pm

theres a bullet type fuse under the bonnet that comes directly off the battery on mine. I guess the obvious would be to use you multimeter to check if theres current getting to the actuator on the compressor. The fact that the fan is coming on etc says to me that the problem lays here somewhere rather than under the dash, but i'm not auto elec either! But it would pay to check all connectors, earths etc you might have touched when installing the stereo

timmo

julian · Post by **julian** » Sun Aug 19, 2007 9:04 pm

Can't find any current running to compressor when switch activated.

Sorry, also should have specified that when I said fan I meant the interior/heater fan. This has to be on for the A/C to work.

The electric engine fan in front of the evaporator/engine does not switch on when button is pressed.

Where exactly do I look for fuses? I am pretty sure mine is a factory install, but from the JDM donor frontcut.

timmo · Post by **timmo** » Sun Aug 19, 2007 10:08 pm

yeah ok i thought you meant the thermo fan. There seems to be some variation in A/C systems, but on mine there is a inline fuse fuse on a wire that runs from the compressor to the positive terminal on the battery. Also check near the drivers side strut tower I remember seeing a blade type fuse for something there on my parts bomb (cant remember if it was A/C or not). Otherwise i dunno how else to help but think about what you might have disturbed when working under the dash

timmo

Bumpty · Post by **Bumpty** » Tue Aug 28, 2007 10:41 pm

ah... we don't need air con in Tassie, just Hardcore heaters in winter!

julian · Post by **julian** » Fri Aug 31, 2007 8:01 pm

Spent some time under the dash today, can't see anything that helps.
Although there is a unit on the passenger side (part #af191-01) that is up behind the glovebox. Little rectangular metal box with large mounting flange secured by one bolt, one of the pins on the input changs between 12v and 0 when AC is ON or OFF. Google calls it an AC control module... What does it do and how do you know if it is busted?

Also, what triggers the AC to switch off to prevent the pipes from icing up? Could this be failing and not allowing the AC to switch on?

keppler · Post by **keppler** » Fri Aug 31, 2007 8:55 pm

have you checked the relays up the top side of the r/h strut

there is a unit mounted on top of the condensor (near the fan) i think 2 yellow wires i am pretty sure this is your thermostat witch tells a/c to turn of

mostly just check power going to relays i had same problem when i first got mine

julian · Post by **julian** » Fri Aug 31, 2007 9:03 pm

thanks keppler, will check...

Matt · Post by **Matt** » Sat Sep 01, 2007 3:01 pm

Also check the Low Pressure switch isn't stopping the current getting to the compressor...

julian · Post by **julian** » Sat Sep 01, 2007 3:16 pm

How would i test low pressure switch? My manual does not cover AC...
And relays replaced with no change (thanks to Sven!).

keppler · Post by **keppler** » Sat Sep 01, 2007 8:33 pm

checking low pressure switch:(located front of left hand strut on a/c pressure line) pull plug off and bridge out with pice of wire then try engauging a/c again

julian · Post by **julian** » Wed Oct 24, 2007 5:05 pm

All right, I still haven't fixed this but have been spurred to action after a horrible windy 35+deg day drive.
Have replaced relays on RH strut tower, A/C controller behind glove box, switch gear on dash and still nothing. Still no power getting to compressor.

Is there an in-cabin thermostat?
Is their one on the engine bay?
Could the electric fan circuit have any effect on A/C?

Where does the wiring from the dash A/C switch go to? I would like to know rather than pull everything to bits...

And lastly, why is it that anytime I work on anything electrical I end up with filthy and bleeding hands, and a bad mood?

Gremlins · Post by **Gremlins** » Thu Oct 25, 2007 8:56 am

Hi Julian, my memory of the aircon side of things is not real good, but the aircon wiring in your car is stock standard australian delivered touring wagon wiring. It is a seperate wiring loom as the vehicles at the time were sold with airconditioning as an option. I'm trying for the life of me to remember where the loom runs, but I know it pops up through the rubber grommet in the engine bay behind the strut towers on one side or the other. It's not a real thick loom as it only has a couple of wires, and isn't completely wrapped in black tape like the normal factory wiring - only has a couple of bits of black tape evenly spaced along the conductors to hold them together. Trace back the wires from the compressor as they should go back to the loom, but it may be via a pressure switch or two. I also think it may run behind the radio so it could be possible that fitting a new radio may have disturbed something. To try and answer your questions, I think the in-cabin thermostat is the a/c control box behind the glove box, there is no engine bay thermostat that I am aware of and not sure which electric fan circuit you refer to, but the radiator electric fan does connect into the optional aircon loom, but I wouldn't think it should stop the compressor kicking in if there was a problem with the fan. If I remember anything else I'll let you know.

Gremlins · Post by **Gremlins** » Thu Oct 25, 2007 9:00 am

Just remembered another thing, when the aircon loom comes out of the rubber grommet into the engine bay it will probably run into a black corrugated conduit and I think this is on the passenger side. The aircon loom has multiple coloured wires, as opposed to the other wires going to corrugated conduit from that grommet which will probably be figure 8 wires of fairly similar colours.

julian · Post by **julian** » Thu Oct 25, 2007 1:17 pm

Thanks Mark,
Will have a look this weekend.

The AUSubaru.com.au Forums

A/C help.

A/C help! 24/10 edit:still nothing!