My truck has the automatic switch on the dash. Its a 2003 and it used to give me problems once in a while but i always check it once a month or so to make sure everything is good. This month the light didn't turn on on the dash saying i was in 4x4 high or low and i did not hear anything engage..... What could be wrong? and could a broken 4x4 anything cause worse MPG??

 

Unless its engaged there shouldnt be any - MPG

 

2 things control that light, the switch and the GEM.

 

try this for me......with your truck turned OFF turn the switch to 4WD and then start the truck ... let me no if it engages .......