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Air conditioning clutch not engaging

Ben123

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Hi All,
This is my first time post seeking some advice on my Toyota LX470 2004 Landcruiser- location Australia.

IMG_8260.jpg
I have purchased after it had an engine and transmission conversion.
The engine is a GM 6.5 TD with mechanical controlled fuel pump, and the transmission is a GM 4L80e with 6 speed conversion and Compushift II controller.
Since purchasing it has tested my knowledge, I still seem to have more questions than answers.
The main issue that I have not been able to resolve since purchasing- I found the air conditioning compressor was hard wired to operate the A/C.
I am not happy with this as the compressor never turns off, I want it to be controlled by the climate control system.
I have returned the compressor wiring to oem. Now when I earth the compressor wire at the ECU the compressor engages.
Problem is the ECU won't switch the earth signal??
A lot of ECU wires are cut and not used due to the conversion, problem is I don't understand the Lexus system enough to know the list of ECU inputs that is required before the engine ECU is allowed to activate the compressor.
Items that have been checked;
Pressure switch circuit checked- all good
A/C on/off switch input signal all good
Thermister sensor checked- all good
Replaced engine ECU- no change
Replaced A/C amplifier ECU- no change
The Stanadyne compressor does not have a lock sensor- 1000K ohm resistor connected to the lock sensor return signal wire (when no lock sensor signal is received the A/C clutch should engage for 5 seconds then switch off. The A/C clutch does not engage at all, at any-time)
The cluster gage tacho has never worked- I have ordered an SGI-100BT signal converter. (I am hoping the engine rpm signal will be the missing ECU input required to activate the A/C)

I hope some-one knows and is able to share all ECU inputs and circuit bypasses required to turn on the compressor.
Some-one may also know how to connect the GM front crankshaft speed sensor to the SGI-100BT.

Thanks in advance,
Ben.
 
Welcome to the forum 123.
I do not understand one thing about such a conversion as this.
Seems with a wiring diagram, a set of gauges hooked to the AC system that it should not be that difficult to get wired up.
Probably follow how the original AC system was wired to the original AC units.
 
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