Jump to content
SAU Community

Stagea Air Conditioning

fmlycar

By fmlycar,
in General Maintenance

 Share

Recommended Posts

fmlycar Proficient

fmlycar

Posted
Posted

I have recently purchased a 1997 s1 rs4 stagea. Car has been converted from auto to manual and is running a r34 power fc. Ran a sensor diagnostics and all ok. I have no power at the compressor or high pressure switch plug. Checked relay ok, fuse in eine bay ok. Is there anything else I should be checking? System has been pressure tested and is all ok. Gassed up and still no compressor running. Want to see if I can sort it myself before I resort to seeing an auto sparky.

Link to comment
https://www.sau.com.au/forums/topic/454013-stagea-air-conditioning/
Share on other sites
zoomzoom Mentor

zoomzoom

Posted
Posted

How did you check the relay?

If you tested the relay itself while removed from the fuse box, and its functioning correctly, probe the pins on the relay harness to earth and measure the voltage. With the relay coil, one side should supply 12v power, while the other side is earthed to the ECU when the ECU wants to switch on the compressor.

The power circuit on the relay should have 12v when the key is switched on, and the other side is earthed through the compressor.

Post up the results and that should narrow it down.

fmlycar Proficient

fmlycar

Posted
  • Author
Posted

Checked all the fuses behind the coin tray and they were ok except for 1 7.5amp which was second in from the right top row, however that didn't have any power at the pins (will check with multi meter tonight). As far as checking the relay, I swapped it out with a k own working one. Haven't bridged anything yet. Might rig up a fused test wire and try that.

  • Like 1
zoomzoom Mentor

zoomzoom

Posted
Posted (edited)

So the wire that goes to the compressor is only a earth?

Yes, one side of the relay power circuit is powered by the battery when the key is in the on position. When the relay activates, the power is earthed through the compressor and it turns on the magnetic clutch. Since that worked manually it seems that circuit is fine.

The relay coil always receives 12v when the key is in the on position, then the ECU grounds that circuits when it wants to switch the A/C relay on.

That is the other main one to check. Have a look on top of the relay for a diagram of which one is the relay coil pins. Unplug the relay and ensure that one of the relay coil pins is reading battery voltage, otherwise that circuit probably has a blown fuse (or worse). The relay coil fuse will be the one I mentioned near the drivers knee compartment.

If you do have battery voltage to one side of the coil, try manually earthing the other side of the coil (with a little jumper wire or similar while the relay is plugged in). That should also activate the relay and turn on the A/C. If that is the case then the issue is closer to the ECU.

Edited by zoomzoom
  • 2 weeks later...
fmlycar Proficient

fmlycar

Posted
  • Author
Posted

It's looking like it is actually to do with the ecu side of things. Anyone know how to get a R34 gt-t ecu to control the ac in the stagea? The original ecu was apparently one of the rare one's, however I don't know how much of the loom has been changed to suit. Is there a way to get the R34 ecu to run my ac? Really like to get this working as it's 40+ every day atm.

zoomzoom Mentor

zoomzoom

Posted
Posted

Pin 14 and 21 on your original loom plug should be all you need to work out. Assuming everything works, when the climate control wants to turn on the A/C, it sends a signal to pin 21 (cant remember if it grounds a 12v signal from the ECU, or actually supplies 12v to the ecu). Then if the ECU thinks all parameters are normal, ie not full throttle or overheating etc, it then grounds the A/C relay, turning it on.

So you just need to find those 2 pins on the power fc pinout and connect them to the correct wires on the loom, if they are in different positions to the stock ecu.

WGC34_Series_1___STAGEA_RB25DET_Auto_ECU_Pinout_translated.xls

fmlycar Proficient

fmlycar

Posted
  • Author
Posted (edited)

Standard ecu according to fast is 0V310 which I have found is rare. I don't have the original ecu to confirm though.

Although every pinout I have seen so far, those wires should be in the same position. However, some suggested that the stagea uses negative switching and the r34 uses positive. How can I get around that if that is the case?

Edited by fmlycar
zoomzoom Mentor

zoomzoom

Posted
Posted

Ive been meaning to make something similar which would make a pull to ground switch into a 12v switch using a 2N3906 transistor, but is was for very rapid switching (a tacho)

In this case couldnt you invert the state by using a small relay? You'll need to be specific whether the AC relay, or the climate control is the affected one.

transistor.switches.pdf

  • 8 months later...
fmlycar Proficient

fmlycar

Posted
  • Author
Posted (edited)

Back probed pin 14 and had no voltage. Pin 21 was 0v ac off and 12.5v approx ac on. Checking pin 14 and it switches ground from what I can tell. Checked continuity with ground on pin 14 and I applies ground when ac is switched on. So where does this leave me?

Edited by fmlycar
  • 2 weeks later...
Dan_J Veteran

Dan_J

Posted
Posted

mine stopped working as well, in the engine bay i found a random ignition source and replaced the ac relay trigger wire with that, sure the relay will always be open when the car is on, but ac will only work when u push the a/c button on climate control

fmlycar Proficient

fmlycar

Posted
  • Author
Posted (edited)

I've tried bridging the ac relay in the engine bay and the compressor clicks but doesn't get cold. Suggestions? Is there another relay in the cabin near the fuses?

Edited by fmlycar

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • MBS206
      Duncan's V37.......race car?

      By MBS206 · Posted

      Even more fun, leave all the ADAS stuff plugged in, but in different locations, hopefully avoid any codes!   And honestly, all these new cars with their weird electronics. Pull all the electronics out Duncan, and just shove an aftermarket ECU and if needed a trans controller in, along with a PDM. Make it run basic but race car styled!
    • Duncan
      Duncan's V37.......race car?

      By Duncan · Posted

      To follow up a question from earlier too since I had the front bar off again (fking!) This is what is between the bumper and the drivers side wheel And this is the navigator side, only one thing but its a biggy! So basically....no putting coolers in the wheel arches without a lot of moving other stuff. Assuming I move to properly race prepping this car I'll take that job on and see how the computers respond to removing a whole bunch of ADAS modules
    • Duncan
      Duncan's V37.......race car?

      By Duncan · Posted

      So I prepped the car for another track day on Wednesday (will be interesting to see coolant temps post flushing out and the larger reservoir, with a forecast of 3-14 being 20o cooler than last time I took it out). Couple of things to mention; since I am just driving the car and not taking a support vehicle, I took the rear seats out and just loaded the back up Team Trackday style. Look at all that space! To cover off removing the rear seat....it is weird (note the hybrid is probably different because it wouldn't have folding rear seats) Basically, you remove the lower seat base, very similar to a r series but it is a clip that pulls forward to release the base rather than it being bolted down. Easy Then, you need to remove the side section of the rear seat on each side. There is a 14mm head nut at the bottom of the side piece, the it slides upwards off a hook at the top to release; you also need to unhook the seatbelt from the loop at the top. Then the centre piece is weird. You need to release/fold the seats forward with the tab in the boot on each side From there, there are 2,x12mm headed bolts holding the rear of each seat to the folding bracket, under the trim between the rear seat and the boot (4x christmas tree clips there, they suck). The seat is out but you can see where the bolts attach to the bracket
    • RP1421
      S15 Spec R

      By RP1421 · Posted

      As discussed in the previous post, the bushes in the 110 needed replacing. I took this opportunity to replace the castor bushes, the front lower control arm, lower the car and get the alignment dialled in with new tyres. I took it down to Alignment Motorsports on the GC to get this work done and also get more out of the Shockworks as I felt like I wasn't getting the full use out of them.  To cut a very long story short, it ended up being the case the passenger side castor arm wouldn't accept the brand new bush as the sleeve had worn badly enough to the point you could push the new bush in by hand and completely through. Trying a pair of TRD bushes didn't fix the issue either (I had originally gone with Hardrace bushes). We needed to urgently source another castor arm, and thankfully this was sourced and the guys at the shop worked on my car until 7pm on a Saturday to get everything done. The car rides a lot nicer now with the suspension dialled in properly. Lowered the car a little as well to suit the lower profile front tyres, and just bring the car down generally. Eternally thankful for the guys down at the shop to get the car sorted, we both pulled big favours from our contacts to get it done on the Saturday.  Also plugged in the new Stedi foglights into the S15, and even from a quick test in the garage I'm keen to see how they look out on the road. I had some concerns about the length of the LED body and whether it'd fit in the foglight housing but it's fine.  I've got a small window coming up next month where I'll likely get a little paint work done on the 110 to remove the rear wing, add a boot wing and roof wing, get the side skirt fixed up and colour match the little panel on the tail lights so that I can install some badges that I've kept in storage. I'm also tempted to put in a new pair of headlights on the 110.  Until then, here's some more pictures from Easter this year. 
    • joshuaho96
      R32 GTS (RB20DE) Injectors Replacement

      By joshuaho96 · Posted

      I would put a fuel pressure gauge between the filter and the fuel rail, see if it's maintaining good fuel pressure at idle going up to the point when it stalls. Do you see any strange behavior in commanded fuel leading up to the point when it stalls? You might have to start going through the service manual and doing a long list of sensor tests if it's not the fuel system for whatever reason.
×
×
  • Create New...