At 11:55 PM 5/26/00 -0400, you wrote:
>Somehow, I just knew you didn't want to do things the easy way. : )
>Well, I'm looking at the ecm pinouts for an 89 F car, and it appears
>that the ecm controls 2 fans. The vettes are similar, but I won't
>swear that the wiring is the same. Pin C1 is for the primary fan, pin
>D11 controls the secondary fan. D11 is wired in parallel with a temp
>switch in the cylinder head.
Looks like D11 is actually sampling the AC pressure switch for continuity
to ground. This is the case on '88, '89 Vette, and '86 F-body pinouts in
my Helms and the diy-efi incoming directory. It uses this input to
determine whether the AC compressor is running, setting the flag for all
the "AC pressure high" options. Looking at the Helms manual, D11 shows up
as strictly an input path.
This creates a new mystery...how do BUAs control the aux fan? There's
logic for it in the .bin but I'm not finding an ECM pin where they drive it.
Hmmm....
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