ECM's and Air Conditioning

[sapearso at rockwellcollins.com]

Getting about ready for the ECM swap on the 88 Toronado. Have a question
concerning the air conditioning. On the oringinal 1228253 ECM, the A/C
request is handled by the HVAC panel sending a request on the data line. On
the 16141470, this request is a discrete input on pin BD11. Will the
16141470 be capable of picking this up off the data line, or do I need to
'T' into the output from the BCM to the '+' side of the compressor clutch
relay? The ECM provides the ground to this relay in both cases. The
16141470 schematic shows that the '+' side of this relay coil is always
energized, while the BCM provides this signal on the Toronado.

Next question, on the schematic for the 16141470, it shows a 'A/C head
pressure' which is supplied a ground by the A/C head pressure switch. What
is this for? I don't see one on the schematic for the Toronado. The
Toronado also lists a power steering pressure switch, but it's not listed
on the schematic for the 16141470.

If anyone wants to see these schematics, email me offlist and I'll send
them to you.

Scott

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