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Tech in Chit Chat, need help with AC on my subaru outback.

Toyoda

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May 19, 2020
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200
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2004 subi outback, 4 cyl with manual ac (auto is set the temp and it stays).
I pulled the system into vacuum, 800 microns (29.8 inhg). It held for a day.
Used a Robinair machine to put 24 ounces in, I still have pressure.

System will not run. I have voltage through the pressure switch (tried jumping as well) but it won't kick the system on. I have power on the ac relay and both fan relays.
If I jump the clutch the system will run and make cold air, I have an electrical issue somewhere.
I can't find the ac module to check for power in and out, but at this point I am guessing that is the issue. I believe I have power where I should but something in the control side isn't working.

If I can't figure out the issue can I add a new switch/relay to put power on the fan relays and ac relay? This would power everything up but wouldn't kick up the idle. The fans should keep the low side pressure down while idling.
 

crispins

FJB
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If I can't figure out the issue can I add a new switch/relay to put power on the fan relays and ac relay? This would power everything up but wouldn't kick up the idle. The fans should keep the low side pressure down while idling.

I have used a switch and relay a few times when working on auto a/c system with electrical issues, it worked fine everytime.
 

Toyoda

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awesome. I figured as long as the fans were on it would work but wanted to double check, I can't afford to rebuild the system.
 

crispins

FJB
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awesome. I figured as long as the fans were on it would work but wanted to double check, I can't afford to rebuild the system.

On my most recent fix, my 1999 Lexus with random ECU modules issues.

I ran a switch and relay to the switched hot side on the relay block under the hood.

This turns the a/c compressor clutch on as well as the a/c fans.
 

Overbear

That Bear
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Somewhere in the PNW
Sounds like it is the auto switch that is being the problem. Go to the junkyard, pull the control module (the whole thing) and relplace yours, see if that fixes it.
 

Toyoda

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Thank you.
Is the ac control module the actual climate control group in the center of the dash? That would explain why I can't find a control module under the dash.
 

Overbear

That Bear
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Somewhere in the PNW
Thank you.
Is the ac control module the actual climate control group in the center of the dash? That would explain why I can't find a control module under the dash.

yes at least in the Forester and STI they are all in one unit. Not 100% sure on your outback but it should be. It should be all one unit together, plug and play.
 

yozsi

Fawk
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Vallejo, CA
Try swapping out the clutch relay. For a few years denso made some shit ass relays and I was changing them out on a daily basis for a while.
 

Toyoda

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I made sure all the relays were working, I was hoping for an easy problem.
 

yozsi

Fawk
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Loc
Vallejo, CA
I made sure all the relays were working, I was hoping for an easy problem.

How did you? They still work and pass some current, but not enough to energize the magnet. So just testing it with a test light, power probe or meter won't work.
 

Toyoda

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Member Number
200
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54
I stuck them in the foglight slot. Same relay part number for all relays in the main fuse box. This gave me visual verification the relay works.
 
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