Aircon problems

[32wbx6]

Hi there from South Africa.

I don't know how many UK busses have or use aircon? Perhaps someone can help me with a problem that I'm struggling with?

About a year ago I finally redid my aircon. The bus originally came with aircon from factory and still has original set up from when she was new. It had lost gas over the years and with new engines etc. I had never got round to re-doing the whole system. Finally, a new compressor, condenser, evaporator, new ali piping etc. Been running like a dream. Using the original LHS rear panel 2.1 system while engine runs off its own new loom on RHS side of vehicle (2.6).

Last few days it stopped working suddenly. Fan still blowing on all speeds, but compressor stops kicking in. Initially thought a gas leak but not that, and had it checked at original installers who did the job.

Discovered that it runs very hot to the point that it has melted some wire insulation and bits if the plastic housing under the rear panel where the main power source connects and the wiring, fuses and 3 relays are.

No fuses blown but just overheats and eventually compressor stops engaging. After cooled down a while it will run again.

I started by undoing and cleaning all plugs, earths etc. Also replaced the few burnt wires with slightly thicker wires.

Runs fine but still gets extremely hot to the touch to the point that the compressor will just stop engaging. This can't be right. I've heard that VW had a problem with this in the early days and there was a "fix" for it. Can anyone shed any light on that or make any other suggestions as to what to look for?

[32wbx6]

[32wbx6]

In the pic above one can see some damaged wiring (already replaced with thicker) and of the two brass threaded blocks to which the main power supply goes the right hand one has actually melted and is loose. I have just placed it back in its housing loosely for now.

[Stesaw]

I'd guess its best to check all wiring and clean all connections, grounds and replace any damaged wiring. I've found with some vans that even though the connections look OK the wires are loose on the terminals which can cause issues for sure.
 

[silverbullet]

Poor earth/high resistance terminal connections will send current draw soaring. I have a factory aircon set which is halfway retrofitted to my bus, melted wiring is not uncommon and my harness is typical.
I do have the factory technical manual for aircon, its only a few pages but doesn't really help with fault diagnosis.
Have you asked on the syncro-sa T3 forum? There will be far more knowledge and experience there
http://www.syncrosa.co.za/forum/