I have pulled the original wiring harness out of my 87 IROC because the system isn't capable of doing what I want it to do. I have installed a FAST ECM with dual sync distrib which is currently installed..

What I am trying to get an understand is how the transmission electronics needs to be wired.

Here is what I know.. The transmission has a top gear selector switch and a Torque convertor switch.

Do you have to use the top gear selector switch in order to use the TCC.

Which wire by color would go to where??

 

In the tranny section, there is a sticky at the top that discusses TC lockup with wiring diags and info on the 700R4. Yours is a tricky year, mid 1987 GM made changes inside the 700R4, so you'll need to follow that sticky and determine which tranny you have, whether you have a NO or NC switch, etc.

 

Oops - it's in the carb section, not the tranny section...