ECU and Wiring - 1986 TransAm. 1986 TransAm. A New Zealand Based Here's the engine bay wiring diagram. I am also sharing the original Coolant Temperature sensor with the GM ECU so had to What is the wiring diagram for a 1986 Pontiac Trans Am? wwwers››American Cars›Pontiac›Pontiac Trans Amsuggestion http://92b4crsod/86wiring/86wiringindex this website helped me figure out how to put the wiring on my 86 TA.