MK3 Air-Con in a MK2

Discussion in 'Mk2' started by Cian, Jul 17, 2013.

  1. Cian Forum Member

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    Planning on converting my MK2 to an ABF shortly. MK2 is an 1988 small bumper that recently had a near fire in the loom resulting in most of the wiring melted so a perfect base for this project!!

    I have a donor MK3 already, complete car and I jump started this evening to see if it would as it'll be moved soon to a mates shed for the strip down. Anyway I noticed that it has air-con which I had forgotten about. It's a Jap-Spec, 5 door loaded with extra's.

    Never thought about transferring the air-con before but with the hot weather recently it got me thinking:

    Is it do-able? Well, anything is do-able, but is it easy enough?
    Anyone done it before?
    Guides, hint, tips?

    Then again, as then MK2 is only going to be the occasional toy, I'm not sure it's worth the hassle one way or the other!
     
  2. rubjonny

    rubjonny Administrator Staff Member Admin

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    if you want mk3 dash easy peasy, if you want mk2 dash slightly more tricky. the a/c section of the airbox is a straight fit, just swap the mk2 air distribution part onto it (the bit with the heater matrix in) fit a new heater matrix and repair the flaps if required. you'll need mk2 a/c glovebox and dash shelf, or just chop your old ones down till they fit. then its a case of adapt the wiring, no worse than the engine conversion really. hardest bit is the a/c controls, either find factory mk2 a/c slider panel and graft it to mk3 wiring, or add your own switches for a/c on and recirculation grafting them ontyo your loom.

    you can get mk2 dash switches for them, these were fitted in mk2s which had a dealer a/c conversion fitted rather than factory fit. the VW vortex is a great source for those. or you could use fog/screen switches suitably adapted, or other car switches glued into a mk2 dash blank
     
  3. whitemk2 Forum Member

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  4. rubjonny

    rubjonny Administrator Staff Member Admin

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    thats just the trim ;) you need the actual slider unit
     
  5. TSR 2.1 Forum Member

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    Do you have a sun roof? ;)
     
  6. Cian Forum Member

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    Right, lots of great info there but my 'drugged up on painkillers' brain ain't taking it in just now. Cheers though

    And TSR 2.1, I do indeed and love it. This was more an rambling thought than me actually wanting to do it. If it seems easy then I might but all will depend on the lads that will be helping me build the car and if they want the extra hassle lol.
     
  7. GVK

    GVK Paid Member Paid Member

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    It'll be snowing by the time you get it done lol
     
  8. Cian Forum Member

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    Eh, probably not far off, that or we won't see much sun for 10 more years lol
     
  9. thegave Forum Member

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    Don't forget ac comes with a hefty weight penalty as well, pretty much all over the front wheels.
     
  10. Cian Forum Member

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    Weight you say? Right, there goes that daft idea out the window...sunroof it is
     
  11. TSR 2.1 Forum Member

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    Good call as a Sunroof = no faff

    So you can now spend that time and energy on something to make it go better :)
     
  12. Cian Forum Member

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    True dat.

    Era the build will be fairly basic to start with as funds are low. This was just a half baked idea with the good weather.

    I'll stick up a build thread in time and ask all the same questions as other have asked [:D]
     
  13. Ozgti New Member

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    Hi guys,

    I have a mk2 non ac car with ce1. I want to put ac in. I have an AQN engine and ac pipes from the firewall forward. What can I use and how do I wire in an ac box?

    If mk3 clips onto the mk2 geater/flaps, how can I get the mk3 ac to work in a non ac car, and are the connectors the same mk3/4?
     
  14. rubjonny

    rubjonny Administrator Staff Member Admin

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    you will first need to decide how you want to control it. the factory mk2 ac system is all vacuum controlled so you need the flap unit, controls, vacuum lines, reservoir, wiring, relay etc. mk3/4 are back to cable controls with the fan control module taking over the control of the compressor, you could use these with standard non-ac mk2 flap unit and controls. mk3 has vacuum recirculation flap actuator controlled by an electronic solenoid, the mk4 is electric motor but only needs to see a voltage signal to open and close so still easy to wire up either way.

    if you want to keep it mk2 dash with mk3/4 fan module you can either hunt out the aftermarket mk2 ac and recirc dash switches, or hook up some brackets to mount lever switches to be pressed when the sliders are moved to the appropriate position :)
     
  15. davidut5 Forum Member

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    The wiring i made using mk3 golf ac/recirc button fitted in the dash 90" rotated, the recirc is still vacuum operated with a general valve from a bmw.
    This is a schematic i made the circuit from, i believe is the final one where i added relay k1 because without it if the engine fan ran it engaged the ac clutch.
     

    Attached Files:

  16. Ozgti New Member

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    So the mk3 unit will physically fit onto the mk2 non ac heater unit? If I use the mk2 flap controls, I need an ac switch (that will be interesting to find...), everything else should work correct? The loom I have has the AC pump wiring on it. I need to check if the pressure switches are on the same loom. If not, I'll have to work out how to get that working.
     
  17. rubjonny

    rubjonny Administrator Staff Member Admin

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    yes you can have any combination of mk2/3/4 flap and fan housings, the fit between them is the same. just the mk4 is different attachment points through the bulkhead and up at the A pillar to mk2/3.

    for mk3 golf the ac harness is integrated into the lighting/engine loom, mk4 its integrated into the main loom from dash side to engine bay side either way easiest way is get donor loom and strip out what you need. the mk4 wiring is probably the easier way to go as more common, it has a single pressure switch and 2 connections to the ecu with a bit of wiring inside for the ac and recirc switches, everything else is handled by the FCM logic. mk2 has a pair of pressure switches and 1 or 2 temp switches, same goes for mk3 except both pressure switches are integrated into a single 4 pin unit

    if you use standard mk2 heater controls 2 of these would make it look OEM:
    https://uk.rs-online.com/web/p/microswitches/0150697

    have one mounted right over at 'cold' and the other triggered on direction slider depending where you want recirculation active
     
  18. Ozgti New Member

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    What's the fcm logic?
     
  19. rubjonny

    rubjonny Administrator Staff Member Admin

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    Fan Control Module, sits under the coolant tank and is the equivalent of the mk2 fusebox and engien bay relays. The module takes care of compressor trigger, ac-on fan trigger that kind of thing :)
     
  20. Ozgti New Member

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    OK. I'm a hands on guy so let me see if I have this right.

    Mk4 ac mounts to mk2 heater box and cables
    I need a mk2 ac switch
    I can run a recirc button or leave it
    I need the body loom from a mk4 to strip and get the ac wires.

    Wiring does my head in (I'm colourblind)!
     

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