Air Conditioning stopped. I've traced faults a fair way, but now hit the wall. It's the fully auto system, though I don't believe any of the "auto" features are relevant to my problems. Not being in a metropolitan area, even if I get AutoLec help, I've probably got more chance of success if I can locate the faults myself.
Firstly, the basics of the parts of the circuits that matter, are fairly simple.
1. From ignition,thru an ACC relay,thru a fuze [#20], to the Air/Con relay, thru a pressure switch, to the ECCS unit, and PRESUMABLY to Earth.
2. From ignition, thru a fuze [#10] thru the Air/Con relay points [closed when relay called, above] to the Magnetic Clutch on the Compressor to Earth.
What happened? Magnetic Clutch windings ere "cooked", and though still working,draw too much current, and blew #10 fuze.
At the time,not knowing what the problem was, replaced fuze. Air/Con worked for a while, then blew fuze again.
Found problem with Clutch, and have obtained a replacement, BUT Have found that now the Air/Con relay [see 1. above] does not operate.
Have tested the Relay - O.K.
Have voltage to the Relay, thru the Relay, to and thru the Pressure Switch. A wire,thru a test lamp,after the Pressure Switch, to Earth, operates the Relay, and Air/Con works.
Question: After the Pressure Switch the circuit goes to the ECCS unit. Does anyone know why, and what happens there? it seems to me that all we need is an Earth, but I'm only used to old time auto electrics, and I'm obviously wrong.
This wire from Pressure Switch, I think, is supposed to go to terminal 46 on the ECCS unit, and is supposed to carry "Power Voltage" when Air/Con is 'off' and Zero Voltage when Air/Con is 'on'.
I have "Power Voltage" on terminal 46 'on' or 'off.'
Can anyone help?? I hope.