IIRC it's in your main box inside the cab next to your hood latch release and on the lower left of the block. It may be a 5A or a 10A who knows after 30 years? Do you have 12VDC at the injectors with key on? A Noid light won't tell you anything if you don't have power to it.Where is the 5 amp fuse located???? If it's the fuse I'm thinking about i checked it but idk if it was a 5 amp
A good point, the grounds by the T-Stat are for the ECM. You need both, power and ground to make a circuit.Forgive me if you’ve already checked this, but have you looked over your grounds? Especially the one on the thermostat housing?
I'm not one to advocate throwing parts at the problem, especially used parts! All that does is introduce other variables to the equation. I don't care if they came from a well running donor, but that's my opinion.