Another ESOF 4X4 problem

[StrokinHarley]

A while back I had a problem with my 4x4 not engaging and it ended up being a dry rotted line at the hub connection. Well with my luck I know have another. I have checked all the 4x4 vacuum lines and there good and they hold vacuum. The 4x4 light comes on and you can here the differential engage. I also noticed when you shift the switch to 4high the A/C switches to defrost however I have no vacuum leak so whats the deal? could it be a solenoid?

Any help would be greatly appreciated

 

[AK Rover]

The HVAC switching to defrost is historically a sign of a busted vacuum line. Since you have checked all the vacuum lines I would inspect the hub seal to make sure they're holding vacuum like they should. My truck had a bad hub seal so I had to manually lock my hubs all last winter but I don't recall it causing the HVAC to switch to defrost. (I use defrost or defrost/floor setting 95% of the time so maybe I just didn't notice.) You could have a bad vacuum pulse motor but I think a bad hub seal is more likely.

 

[W4RLR]

Check the vacuum solenoid on the inside of the engine compartment, passenger side. If it goes bad, it can't provide enough vacuum to activate the hubs. A new one costs $83 at the dealer, I fixed all of the problems you describe with a new solenoid. All of my vacuum lines were fine.

 

[Skydogfarms]

Vacuum solenoid

I just replaced my vacuum solenoid last week. It fixed all of my troubles. The A/C would not work when I selected 4x4.