I have a 07 Lariat with vacuum 4X4 switch. Goes in and out of 4 Hi and Low however dose not light up on dash for 4 Hi only( 4 Lo lights up ). Is this the beginning of a vacuum leak or bigger problem? Thanks

 

I'm having the same problem with my 07 also. The light comes on when I turn the ignition on so I know the light works but it doesnt light when I engage 4HI. Anybody have any ideas???

 

my 08 xlt was doing the exact same thing.....new iwe solenoid on the firewall fixed it. got it from carquest dorman part number 600-400. it was like 23 bucks I think

 

I finally got around to ordering the : Dorman 600-400 4WD Vacuum and Emissions Purge Solenoidand and it fixed my problem. I ordered it on Amazon.com and the total with shipping was $23.02 and I used 19.68 in amazon rewards points so it cost me $3.34. It showed up in just a few days and took less than 5 minutes to replace and now I have a working 4X4 Hi light.