I have a 2005 f250 super duty my 4x4 won't engage it worked great about a year ago none of the 4x4 lights come on ether
If the 4x4 light doesn't come on, it is likely an issue with the solenoid in the transfer case or, less likely, an issue with the switch itself. Were it a vacuum issue at the hubs, the light would still come on, but the hubs wouldn't lock.
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