Ok been fighting this demon for almost a year on this truck I have replaced the Fic and had Mack dealer test my Vmac module when he reprogrammed my fic and it was all good ..well my truck still wont run ..ugh ..so my actuator is not working so run thru the actuator test and it all leads right up to test 64 ..when I perform the test the actuator wont move ..I put the voltage tester on the jumpers when performing the test and I have 12.75 volts F1 but when I touch E4 to ground the voltage just drops out to 0 from F1 and actuator dont move ...now if I touch the F1 and E4 jumpers directly to +and - on the battery the actuator moves and hits the stops and I started the truck doing this ,it fired right up ...my question is do you think that actuator is bad like the book says ...or do you think maybe I have another underlying problem like bad ground or sensor ect dropping power out ? What is weird is i have my voltage meter on the test leads when i put them on the battery and move the actuator and meter reads 8.75 volts ...but battery is fully charged to 12.75 volts .