problem with 4x4 98 f150 5.4l
problem with 4x4 98 f150 5.4l
2 solenoids on firewall, one for engage and one for disengage, Both are brand new, engage solenoid has 12v to one wire and ground to the other like its supposed to, disengage solenoid has 12v to both wires on the connector...what could cause this issue?????
What you measure depends on what function has been selected.
In 2wd, you will measure 12 volts on 'both' terminals 'both' solenoids because ground is missing so neither solenoid operates.
In both 4wd H and L only one solenoid will have 12 volts and ground to operate, passing engine vacuum to the front actuator.
When 2wd is requested, one opens from ground removal, the other operates to disengage the Actuator (until the case motor) comes back to 2wd rest, then it's ground is removed as it's no longer needed.
The case motor circuit board supplies the grounds from the GEM as needed. This is how the dash lights are turned on and off per the function.
Just common sense..
.
.
In 2wd, you will measure 12 volts on 'both' terminals 'both' solenoids because ground is missing so neither solenoid operates.
In both 4wd H and L only one solenoid will have 12 volts and ground to operate, passing engine vacuum to the front actuator.
When 2wd is requested, one opens from ground removal, the other operates to disengage the Actuator (until the case motor) comes back to 2wd rest, then it's ground is removed as it's no longer needed.
The case motor circuit board supplies the grounds from the GEM as needed. This is how the dash lights are turned on and off per the function.
Just common sense..
.
.
Last edited by Bluegrass; Feb 8, 2019 at 10:15 PM.






