MF6400 Air Con Issue

Discussion in 'Machinery' started by Steevo, May 16, 2019 at 7:04 PM.

  1. Steevo

    Steevo Member

    Location:
    Gloucestershire
    Had an air con guy out recently as the air con wasn't working properly on this tractor. Tested, re-gassed etc. but still not working. He's suggested calling the dealer as thinks it might be a laptop job to plug in an test/diagnose.

    By all accounts the temperature switch/dial in the cab doesn't click when it reaches temperature and has advised it "might be the thermal unit".

    Anything else worth considering before picking up the phone to the dealer?
     
  2. Is it a climate control unit? Temperature comes up digitally or just normal control knobs?
     
  3. Steevo

    Steevo Member

    Location:
    Gloucestershire
    Just normal control knobs-fan, hot/cold and air con temp.
     
  4. Ah sorry, had an issue before with the climate control not working properly and requiring calibration but had no problems with normal controls
     
  5. Speedstar

    Speedstar Member

    Location:
    Scottish Borders
    on a standard 6480 you do not need a laptop to sort the air con ,
    check has it got gas in it ?
    is the compressor or going in & out ?. Check the relays as they can be trouble
     
  6. Steevo

    Steevo Member

    Location:
    Gloucestershire
    Thanks. Yes the air-con guy has regassed it so it’s full. He checked wiring from cab roof onwards and apparently it’s all good, but no power getting to the wiring that goes to compressor etc hence he suspected an issue prior to this, noted as the “thermal unit”.
     
  7. Speedstar

    Speedstar Member

    Location:
    Scottish Borders
    when you say no power , have you by passed the low & high switches to get the compressor to run ?
     
  8. Steevo

    Steevo Member

    Location:
    Gloucestershire
    Not a clue if i’m honest.
     
  9. Lofty1984

    Lofty1984 Member

    Location:
    Cardiff
    As speedy says I had a similar problem temporary fix was to run a cable direct from the compressor to the 3 pin plug in the cab
     
    Steevo likes this.
  10. Steevo

    Steevo Member

    Location:
    Gloucestershire
    Thanks. The air con guy seemed to know his stuff and does tractors a lot. He said he thought the air-con was part of a CANBUS system and was concerned about making things worse.

    Potentially not the case then based on the above?
     
  11. Steevo

    Steevo Member

    Location:
    Gloucestershire
    Would this be a case of bridging the terminals behind the temp switch in the cab?

    The air con guy suggested the switch didn’t click so he thought it unlikely there was power going to it.
     
  12. Speedstar

    Speedstar Member

    Location:
    Scottish Borders
    you may be better to get the mf guy out to it if you not sure how it all works .
     
    Steevo likes this.
  13. Bullring

    Bullring Member

    Location:
    Cornwall
    Mine didn't work but it turned out to be the relay, does it click and kick in the compressor when turned on.
     
    405mi16 likes this.
  14. Steevo

    Steevo Member

    Location:
    Gloucestershire
    No, no clicking.
     
  15. essexpete

    essexpete Member

    Location:
    Essex
    Bridge out the thermoset? How I diagnosed my Ford NH.
     
  16. made2fail

    made2fail New Member

    hi, i'd put all the money in my wallet on the relay at fault, changed loads of these. its the worse relay to get out from the fuse box.its in the top left hand corner & sometimes need to lift the hyds lift panel out to gain extra access to the relay.
    sometimes if you have the ac on as you rock the relay you hear the compressor clutch click
     
  17. Dave6170

    Dave6170 Member

    Location:
    Watten, caithness
    It was the relay on mine last week.
     
  18. raiderz

    raiderz Member

    Location:
    County Durham
    I had problem on a 6616, the receiver dryer had failed and filled the pipes going up the cab front pillar to the radiator at the top with tiny little grey balls, what a mess on it was for the fitter to clean it all out. Glad it was still under warranty though, most of the components were filled with these balls and needed replacing.
     
  19. Steevo

    Steevo Member

    Location:
    Gloucestershire
    Thank you all. Seems there's a pattern here.

    Worth checking the relay as a cheap fix before shelling out again. (y)
     
    Dave6170 likes this.
  20. farmerphilly

    farmerphilly Member

    I had the same issue and yes it was the relay. I swapped it with one from lights on the steps and they flickered on and off. New relay for about a fiver and been ok since. You might need to take the trim off around the pto levers to see the relay as I seem to remember it is in the very top left of the circuit board.
     

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