Hello everyone, I’m having some troubles with my fathers 4x4 in his 2003 F150. I switch it to 4wd, I hear the clicking in the dash, the light comes on, all vacuum lines work all the way to the bottom where I can see it suck the pin in just like it should. Everything seems to work but I can’t for the life of me get in into 4x4. Please help and send suggestions

Thanks!