Electronic switch makes a "click" and dash indicator light up, but 4x4 does not engage. Any help or advise will be apreciated

 

sure its not engaging?? after the click it takes like 5-10 secinds for everything to hook up together.

 

mines doing the same thing!!!!!!!

 

check your vacuum hose from your firewall to your front transfer case. The vacuum hoses they use tend to corroid from heat and battery acid. The vacuum lines start from a solenoid in the firewall right behind the battery. follow that all the way down to the transfer case. I found a small hole in mine which caused the same problem. I think thats a good start

 

On that last post i meant differntial not transfer case. sorry for the mix up

 

Thanks i'll check it out as soon as the temp get's over -10

 

I have a 2000 F150 and when the weather got real cold a week ago the 4wd stopped engaging. The light would come on on the dash but that was it. I crawled underneath and watched the vacuum actuator to see if it was working when someone turned the switch and low and behold it was not. Next step was to check for vacuum. There are two hoses at the actuator on the diff when the switch is set to 4wd only one hose should have vacuum which it did. The next step was to take a heat gun and heat up the vacuum actuator which worked like a charm. The idea is that condensation builds up over time and when the weather gets low it freezes the diaphragm. To keep it from happening again I bought some air brake line antifreeze and put some in the vacuum lines and diaphragm. Long story short, the 4wd is working as usual but I have not had the antifreeze in long enough to see if it works. Give it a try and I bet that fixes your problem. Good Luck.

 

It was the actuator, I got back in town thursday and did as you said. Everything works fine
Thanks