<html>
The LT1 PCM s are not forgiving in this area. When AC is
Fully operational , PCM is watching the AC <br>
line pressure status and coolant temp . Any attempt to run 2nd and
3rd fans manually , likely will set a DTC.<br>
I would think , a hard wired approach , so the PCM can't see what
your doing may be the only work around.<br>
Also there is a thermocouple device inserted in the Heater Core
for additional monitoring , for heating<br>
and defrost mixing temp control , which is using the AC compressor
as balance / blend.<br>
This is a simplistic explanation of the HVAC in LT1 s. The
introduction of R134A refrigerant also ushered in <br>
additional complexity into the systems. In a Hot Rod , might
be easier to install an Independent fan with<br>
a temp delay when AC is enabled. Just my 2/c.<br>
Len <br>
<blockquote type=cite cite> <br>
<font face="arial" size=2>Any one able to help here?.</font><br>
<font face="arial" size=2>The PCM is being used in a vintage hotrod, and
I haven't a clue about what parameters the pcm is looking for, and
any help on the DTCs or info in general appreciated</font><br>
<font face="arial" size=2>Bruce</font><br>
<br>
<font size=2>I want the pcm to turn on the cooling fan when the A/C
compressor is on, to draw air through the condensor.</font><br>
<font size=2>If I put and power to the A/C inputs to the PCM eg: A/C
request, clutch status, I get DTC,s.</font><br>
<font size=2>It would be really nice if I could get someone to turn off
the DTC flags for the A/C stuff.</font><br>
<font size=2>I need some insight about the 94 -95 Lt-1 PCm's #
16188051. </font></blockquote></html>