70 Duster Starter Relay Voltages

this might not tell you anything new but might confirm in your mind

get under the car if necessary with a meter, and jumper the 2 solenoid terminals directly across. check voltage while cranking. if you have 10V (hopefully more) at the starter to the starter ground while jumpered, then you are getting enough juice to the starter.

if it won't crank then, you have either starter internal problems, or engine problems, assuming the starter gear is not jammed.