Quote:
Originally Posted by hatzie
It should work just fine without terminal D connected. Terminal D is a slightly different diagnostic tap for the ALDL port and the ECM in 89 and an EGR bleed solenoid on some earlier rigs. IIRC the ECM controls EGR bleed on the TBI rigs.
Whoever did those 82-86 wiring diagrams at GM should be hung, drawn, and quartered... They didn't label the transmission side connector with terminal letters and they show wire side on both so it's easy to mis-read the two terminal diagrams. You have to mentally think about where things would be if you plugged the connectors together. If you look at one of the diagrams with EGR purge and three terminals it becomes clearer what's happening.
The 89 transmission should have an additional thermal switch in the internal TCC circuit but that won't affect the external wiring.
You should find and install a Low Vacuum Switch. The Low Vacuum Switch cuts power to the TCC when manifold vacuum drops from the throttle opening. It's an analog lockup control so you don't burn up the TCC by applying torque without cutting out the clutch. You definitely need it to utilize the TCC without damaging it.
Make sure the brake pedal switch has the TCC switch contacts as well... The standard transmission brake pedal switch doesn't have provision for this.
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Lucky for me when the previous owner swapped my rig to a SM465 they were nice enough to tie the wiring up and leave it hanging under the hood by the brake master cylinder. So I have the brake and low vacuum switch, my concern was the internal wiring with it having 2 of the wires going to the ECM. So on the 1989 transmission I just use the A and B terminals and just forget about the C? Here is a close up of the internal wiring. Tell me if I have it right or correct me. Thanks Hatzie