Range Rover Aircon

I bought second hand air conditioning parts from a Discovery which was being broken up for spares a few years ago.  The parts had just sat in my garage ever since.   I have finally fitted as much as I reasonably can, leaving just the compressor (which will be fitted after the fuel injection pump has been rectified) and its belts (the pulleys will not be fitted until the compressor is on) and the high pressure pipe between the condensor and the pressure switch (the one I have is corroded through and useless).

Fitting the aircon heater box was in theory simple enough – it was a direct replacement for the original unit which was identical except for lacking the evaporator.  However, on a Range Rover, this entails removing the entire dash assembly, which was a pretty scary prospect.  Series and Defender vehicles have self-explanitory dash panels with exposed fastenings, but not so the more upmarket models.  A little help from a friend saw the dash removed in a few hours, though.

Swapping the matrix boxes over went easily and quickly, as expected, and the “new” unit appears to be in excellent condition with no damage or even any dirt.  Connecting up the heater controls is very simple, but you do need to make sure you set the Bowden cables correctly for full movement.  The aircon button was added, along with the control panel wiring sub-harness (which differed from the original only in having the extra plug and wires for the aircon button).  Thankfully, the RR’s main harness already had the aircon wiring fitted, so this addition was simple.

Before refitting the dash, we needed to ensure the engine bay electrics were all sorted.  The body harness, which runs to the aircon pressure switch and the condensor fans was all present and in good order (though the fans’ relay was in the opposite footwell from what was indicated in the LR manuals).  However, the RR engine sub-harness lacked the aircon pieces, namely the compressor clutch control and two thermostatic sensor couplings and wiring.  This needed to be transferred from the donor Discovery’s harness, which had been bought along with the rest of the parts for this very occurence.  However, the Discovery was a post 1996 model, which has several changes over the earlier 300Tdi Discovery models.  This included the engine and main harnesses and their plugs, so it was not possible to merely copy the Discovery wirng and transfer the aircon wires to the RRC plugs at the same positions.  A lot of careful study of the LR electrical fault finding manuals for both the soft dash RRC and 1996+ Discovery eventually revealed the answers, and the RR engine harness recieved its additions.  Thanks to Rogers of Bedford for lending me those manuals.

The result is a factory specification soft dash aircon harness, right down to the wiring colouring and sheathing.  The aircon system will be indistinguishable from a factory fitted system, using all original parts and layout.

Refitting the dash was a little less daunting than removing it.  A few light bulbs blew in the process, mainly the little green ones that internally illuminate the switches and one of the white bulbs that front-lights the speedo and temperature gauge, but other than that, there seems to have been little trouble.  They have all been replaced and the dash lighting is all good again.

I took the opportunity to clean up the dash and sort out a few niggles, like a rattly transfer box selector (one of the top-hat plastic washers was missing at the gear box end of the linkage from when I’d had the clutch replaced) and a few squeaks fromtthe dash itself have been sorted.  Apart from the front end of the centre console, which is creaking on its mounting bracket (to be sorted with neoprene tape), it’s all much quieter now.

I’ll have to wait a while before I can test the aircon system works properly, but I can’t see any reason it shouldn’t – all the parts seem in excellent condition and the controls all seem to work correctly.  I should have a more comfortable summer now; RRCs have acres of glass which make them a hot place to be in sunny conditions and slow traffic!

I have also sorted out the SRS warning light and reset the airbag system, borrowing Rogers’ Autologic diagnostic computer (after repairing it for them 😉 ).  The “fault” was me – it was an induced error reading from turning on the ignition with the driver’s airbag disconnected while fitting the new indicator switch.  A no-cost fix is always pleasing…