Sorry to bump such an old thread but it's relative to my interests atm. I have a 94 Ranger with no TCC lockup. I tested voltage just out of the computer and got no signal to the solenoid to lockup. Should I repeat the test with the multimeter tapped in closer to the connection at the transmission? Has there been a resolution as to whether adding a manual lockup switch will cause a CEL? Or any other problems that might arise from switching the solenoid manually vs replacing the PCM?

Thanks!