Cmosfet Posted August 3, 2014 Share Posted August 3, 2014 Hi all, I am trying to find out why the electric fan in my 1991 loyale is not coming on with the A/C. From what I understand it is supposed to come on when the a/c kicks on or when the thermoswitch on radiator trips. The fan itself works fine when i disconnect the thermoswitch and short the connector. I bench tested both relays behind pasenger strut tower. One is a/c clutch and the other is the fan i believe. I searched and searched for help before posting. Also cannot find schematics on line yet for ea82. Still searching... I will also look for a book to purchase. Have a chiltons that came with car and the two subaru fsm pdf's but no info there i can see. Am i missing a relay or fuse? Thanks in advance for help!!! Quote Link to comment Share on other sites More sharing options...
Gloyale Posted August 3, 2014 Share Posted August 3, 2014 Which time is fan not comoing on? A/C-defrost? or Tempature based? Tempature fialure would be the thermoswitch in the radiator...or it's connector, or it's ground supply...etc...... A/C failure would most likely be an issue with the pressure switch/low pressure/ or maybe the pulser coil or thermostat for the A/C inside the EVAP unit (behind glovebox) Definately check all fuses and fusible links first. Quote Link to comment Share on other sites More sharing options...
Cmosfet Posted August 3, 2014 Author Share Posted August 3, 2014 When i turn on the ac/defrost. I have not checked the actual thermo switch yet. I checked the pulser by turning on the ac and unplugging the pulser connecter on the compressor. This disengaged the ac clutch. I think this means the ecu sees the pulser signal? Ah, fusible links... I will check those. And look behind glovebox. Quote Link to comment Share on other sites More sharing options...
Loyale 2.7 Turbo Posted August 3, 2014 Share Posted August 3, 2014 There is a "Main" A/C Relay inside and is prone to fail with age, look for photos here: ~► http://www.ultimatesubaru.org/forum/topic/87523-how-to-swap-the-old-roundie-relays-with-standard-bosch-relays/ Kind Regards. Quote Link to comment Share on other sites More sharing options...
Gloyale Posted August 3, 2014 Share Posted August 3, 2014 Check the microswitch in the drivers footwell area.....on the side of the EVAP box. But most likely the A/C line "Main Fan switch" pressure switch is probably not closing........This switch closing is what powers the "fan relay", which then connects the Fan motor to ground. If the System is low on pressure, the compressor not pumping, or the switch defective it will not transfer "on" power to the relay. Quote Link to comment Share on other sites More sharing options...
Gloyale Posted August 3, 2014 Share Posted August 3, 2014 Here's the fan power itself...... And here's the likely Hitachi A/C system you have. Heres the panasonic system too...(likely only on RS or other high end w/MPFI) Quote Link to comment Share on other sites More sharing options...
Cmosfet Posted August 3, 2014 Author Share Posted August 3, 2014 Loyale 2.7 turbo...yes i read your excellent write up on relays. And also the electric fan conversion, very nice. Plan on doing some of that once i get the vehicle running good(and licensed:) i recently purchased it and it needs lots of love. Having fun working on it and learning. Way easier to work on than the sti. Gloyale... Yesssss thank you sooo much for the schematics. Im on it now. It is the hitachi system and it blows cold air. I do not know much at all about ac systems so i guess it could be low on pressure and still blow cold air? If that switch is bad or not tripping, wonder if it is the cause of my idle not going up when ac is on. ...studying schematic... THANK YOU!! 1 Quote Link to comment Share on other sites More sharing options...
Loyale 2.7 Turbo Posted August 3, 2014 Share Posted August 3, 2014 Loyale 2.7 turbo...yes i read your excellent write up on relays. And also the electric fan conversion, very nice... Thank you for your Kind Words. ... wonder if it is the cause of my idle not going up when ac is on... In the Carbureted EA82's the A/C system has a vacuum line coming from the intake manifold to an electric switch, located close to the two A/C Relays in the engine's bay; that switch sends vacuum via another vacuum hose to an accelerator actuator next to the accelerator's cable plate, every time the A/C is turned on... and thus explains how the RPM's raises everytime the A/C is On. Somehow I'm not sure right now how that configuration changed for the EFi EA82's ... however you can search for vacuum hose(s) unplugged, cracked or missing around those areas. Kind Regards. Quote Link to comment Share on other sites More sharing options...
86 Wonder Wedge Posted August 3, 2014 Share Posted August 3, 2014 I thought I had a bad fan at first, but the fan only trips when the radiator temp rises too high or the low side A/C pressure is too high (which is why it's called a trinary switch). It's really only meant as back-up cooling. In the 2+ years I had my 91 sedan, it only came on twice: Hot summer day (95+) with the A/C on full tilt at a long light and when I had the A/C on (testing cooling ability) in the garage with a warm car, warm day. Normally, I could let the A/C run on a decent day and let it idle and the mech fan kept the temp normal, easily. Quote Link to comment Share on other sites More sharing options...
Cmosfet Posted August 4, 2014 Author Share Posted August 4, 2014 This is a SPFI unit. Im thinking the computer gets a signal that the ac is on and adjusts the IAC valve to kick up idle. Well using the schematic i disconnected the trinary valve and shorted the two wires triggering the fan relay and it came on. 86 wonder wedge: oh ok, everywhere i read it said the fan came on when ac is on. So i figured it always did. Is there a way to test the switch? Or maybe just run it and see if it trips. Its been near or at 100 here for quite awhile and will be for some time:) I will remove the thermoswitch and test it with boiling water, just to make sure that works. I like switches so i will probably add a switch to trigger the relay. Here is a pic of the engine... I hear everyone likes pics. I clean on breaks makes it funner to work on for me. Thank you all for the help. Now i need to replace some hoses and get the air bubbles out of cooling system and on to other issues. Quote Link to comment Share on other sites More sharing options...
Cmosfet Posted August 4, 2014 Author Share Posted August 4, 2014 Hmmm, must read on how to post big pics....kinda a newb ... Quote Link to comment Share on other sites More sharing options...
wagonist Posted August 4, 2014 Share Posted August 4, 2014 Thank you for your Kind Words. In the Carbureted EA82's the A/C system has a vacuum line coming from the intake manifold to an electric switch, located close to the two A/C Relays in the engine's bay; that switch sends vacuum via another vacuum hose to an accelerator actuator next to the accelerator's cable plate, every time the A/C is turned on... and thus explains how the RPM's raises everytime the A/C is On. Somehow I'm not sure right now how that configuration changed for the EFi EA82's ... however you can search for vacuum hose(s) unplugged, cracked or missing around those areas. Kind Regards. The dealer fits A/C looms here have an extra single wire plug which then plugs into the main loom for EFI cars. When the relay for the compressor clutch connects, this wire sends a signal for the ECU to idle up. I always wondered what the extra wire was until I got an EFI EA82 Out of curiosity, is the A/C clutch kicking in & out in normal operation? Because the entire A/C system won't work if there's no gas, including the relays. Quote Link to comment Share on other sites More sharing options...
Loyale 2.7 Turbo Posted August 4, 2014 Share Posted August 4, 2014 The dealer fits A/C looms here have an extra single wire plug which then plugs into the main loom for EFI cars. When the relay for the compressor clutch connects, this wire sends a signal for the ECU to idle up. Thank you for the Explanation. Kind Regards. Quote Link to comment Share on other sites More sharing options...
Cmosfet Posted August 4, 2014 Author Share Posted August 4, 2014 The ac turns on and blows nice cold air. I have not let it run long enough to see if it cycles. I will do so tonight and see. Where is this single wire connection? By the relays on pass strut tower? Mine definitely does not idle up when ac is on. It will icrease then drop below normal idle. Quote Link to comment Share on other sites More sharing options...
wagonist Posted August 5, 2014 Share Posted August 5, 2014 I'm not sure how the system is there. Cars delivered to Aus had no A/C wiring fitted from the factory. The coldest state here still hits 25 degrees C in summer, and a lot of places are consistently over 40 degrees C, so why A/C wasn't fitted as standard, defies me So we've got this extra loom which was pulled behind the dashboard and out through the 2 rubber grommets in the top rear corners of the engien bay. Looks U G L Y Anyway, this extra plug on our is on the driver's (right) side under the dash. Is a blue single pin plug. However, I've noted that this loom is made for both LHD & RHD (ie has 2 different positions for the line pressure sensor (ours is on the LHS strut tower, I believe LHD ones are behind the RHS headlight). I can't remember if there was a 2nd blue plug on the LHS of the dash or not, so maybe also look behind the glove box? I have seen a loom which had the factory fit A/C wires & this was different again Hope that hasn't confused you... Quote Link to comment Share on other sites More sharing options...
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