The signal wires from the A/C and power steering don't connect to the
ECU. They do connect to the Idle Control Unit. The wires are in the FI
harness whether needed or not, at least on the USA models I have seen.
The wire needed for the A/C Compressor On signal is a single white/green
stripe wire with plastic connector that sticks out of the main FI wiring
bundle near the ignition coil area.

Good luck with the Bentley diagrams for this wire. Not shown fully and
what is shown is misleading. Look at the FI diagram for the ICU and you
can see an unused wire coming from pin 2, white/green. Look at the A/C
diagram and see a wire from the compressor clutch labeled "to idle
stabilizer control unit" but wire color shown is red/blue and no mention
of exactly where it goes. These two get connected for the A/C signal to ICU.

Mark

BenT Syncro wrote:

> On 8/20/07, Kim Springer <kimspringer@rcn.com> wrote:
>
>>I recently got the AC runnig in my truck and think I need to step up the
>>idle for the extra load of the AC compressor.  The engine has stalled a few
>>times and the rpm takes too long to stabilize off revs.
>>
>>I haven't looked at the Bently wiring diagrams, but I would guess that
>>there is a contact on the Idle Control Relay to do this.  I would also guess
>>that it's just a matter of running an extension from the clutch wire to the
>>relay.
>>
>>Anyone done this?
>>
>>Thanks,
>>
>>Kim
>>88 Tristar #7
>
>
>
>
> Not sure what engine management system you have but I thought the Digifant
> ECU did all the idle compensatiing for the AC and PS. True or false?
>
>
> BenT
>