North American Turbocoupe Organization



A/C and Fan operation revisited
Matt S Offline
Posting Freak
#1
So what activates the fan when the AC is on? Is it the pressure switch?

I also would like to add a switch to bring on one or both of the fans when it gets warm, before the engine heats up. Earlier someone posted a great write up on putting in a bosch relay with an under-dash switch. For the life of me I can't find it; so I'm thinking of tapping into whatever gets the fan working when the compressor kicks on.
I'm also asking as my freon is gone, and I want to be able to push in the A/C switch to get some cooling, even though the compressor is not hooked into a belt. At least until I rebuild with r-134a
Or am I nuts? (I'm used to hearing I'm nuts!)
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Pete D Offline
Administrator
#2
The "How To" is in the Tech articles section

If your freon is gone all the pressure switch will do is cycle the fan and the compressor on and off rapidly. You won't get any real cooling for the passenger side fan by turning the A/C on.

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NATO Member. it's not a vice, it's an obsession
"The nice thing about each new day is nobody ever used it before" Barnaby Jones
88 TC X 2, 86 SVO, mods list at
http://www.turbotbird.com/showroom/pd_88tc.htm

[This message has been edited by Pete D (edited 06-27-2002).]
Pete Dunham


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Jeff K Offline
Administrator
#3
When the A/C clutch relay (located in the IRCM) turns on, the main fan (pass side one) is also turned on. The A/C relay is triggered by the CCPS (cycling clutch pressure switch) located on the top of the accumulator. WHen the A/C clutch relay turns off, so does the main fan. The pressure switch in the high side A/C hose is set to turn on the aux. fan (driver side one) when the high side pressure ixceeds 310 psi, which it will do in a real hot day. If you are low on R12, the CCPS will cycle on/off rapidly. If you are totally out of R12, the CCPS will never turn on.

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Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 20 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 00 Windstar (wifes vehicle)
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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Matt S Offline
Posting Freak
#4
Ok, I'm just plain blind. Thanks Pete! That's the one I was looking for; only it was in my blind spot yesterday...

Yep, it's empty, and cycles every 4 seconds. But I guess I won't get any real cooling from the pass side fan, so I'll wire in the relay.
Lots of traffic, and even when it's only 50 degrees here I sit long enough and get nervous about it getting so hot.
Thanks both.
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Hawk Offline
Senior Member
#5
Matt,

Before going to all the trouble of what you are proposing, I would verify whether your car really is getting hot. The gages in TCs are known for being inaccurate.
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Matt S Offline
Posting Freak
#6
Yeah, I just don't like to wait for the fan to come on. If I remember what I read correctly the fan comes on much hotter than other cars...
But it really comes down to me being anal about it. Don't know, hearing the cooling fan cycle 10 times in a mile of moving just makes me nervous somehow on this car. I could care less about it in my other cars; but then again I have 2 extra working engines for my others...! None for this. Parts are hard to find. I've actually found a few junkyards up here where the people didn't even know there WAS a 4 cyl turbo in a tbird...!
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2birdsinthefalls887 Offline
Senior Member
#7
hey Matt S, if you unplug the clutch cycling switch on top of the accumulator and remove the screw in it,then plug it back in the fan will come on in a/c or defrost mode,just remember to un plug your compressor.

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87base turbo coupe 120,000 miles, mods auburn diferential with 3.73 gears,140 mph speedo,adjustable camgear set at 4degrees advance, and of course the A&A wing.88turbocoupe 166,ooo miles factory moonroof,autolamps,powerseats,premium sound with equalizer,no mods,got car for free and is not worth it, it's an automatic.daily driver
been to carlisle 2002,it was great!!!
87 T/C,base, 5spd, bright red metalic, 136,000 miles. My pride and joy of the fleet.
88 Turbo Coupe,loaded 104,000,
88 Turbo Coupe,Fully loaded,
Been to Carlisle 2002,2003, 2004,2005,2006,2007
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