94 Dakota Wipers not working

[64conv65hard]

Wife's 94 Dakota wipers stopped working. Checked fuse and was good. Using test light at plug to motor, when wiper switch turned on (ignition on) Blue wire is hot, Red is hot, brown is hot, green nothing (assuming ground?). Checked all again with meter and all 3 are showing 12V (with wiper switch on). Bought new wiper motor believing that it was bad since it was getting power and after replacing, same problem, getting power but wiper not working. I do not have a manual for this truck and am now stumped. Any suggestions on what to be looking for?

 

[65 sporty]

The diagram I just found, it looks like the blue is power w/key in run, red is high, brown is low, green is park, the motor should ground to the cowl/firewall. If I go to the shop later I will check to be sure this is correct, sometimes the internet diagrams can be wrong.
I have run into lots of GM trucks where they loose ground to the firewall

 

[64conv65hard]

65 sporty, thanks for the response, after reading your post all makes sense. I was using the battery negative post for my test light and that's why I was showing conductivity. Went out and cleaned the ground jumper on the mounting plate and now they work. $50 motor so still a cheap fix (and something learned) on old trucks.