I have f-150 4x4 it is a 2000, it will not go into 4x4 the vacuum actuator
on the front diff wont engage. If I use a jumper hose at the two silonoids
on the firewall i can get it to engage and then switch the jumper hose to disengage. my climate control switches from panel to defrost whenever it comes under load.
I checked the vacuum bank behind the battery box and the hoses but cant find any leaks anywhere. Would someone have a idea to my trouble...