Hello experts, couple of months ago my Comanche died, would crank till the sun went down but wouldn't fire. Replaced everything spark side and it ended up being the ECU. Plugged it in and it fired right up, ran great (other than mud in the intake from a big puddle) then I was driving and it just quit. Radio, lights, all electronics worked just fine but the truck died, same issue. Today I pulled the ECU out and pulled the back off. The R125 (resistor/transistor not sure which) is broken, I didn't take apart the first ECU so I don't know if it's the same problem but I'm assuming it is. Does anyone know what this is and/or what's causing this problem?
89 Comanche
Factory 2WD, converted to 4WD
2.5l, AX5 manual