05 f350, 4x4 not working

[dieselpower65]

Hi my 4x4 is not engaging into 4 high or 4 low, it will only stay in 2wd. the light for the switch is not on so i took it off and took it apart and cleaned it i got the light to flicker on and off when i plugged it back in. So do i just need to get a new switch or where should i start diagnosing the problem to fix my 4x4

Thanks

[russf]

First of all lets start with the basics. When you switch it to 4x4 does the front driveshaft turn with the wheels off the ground? If not, electrical issue, possible t-case issue. If so, check vacuum.

Make sure your vacuum pump is working, you should hear it turn on, with key on engine off, and you could try changing your interior heater vents from floor, to dash level make sure it changes. Next there is a vacuum line by the vacuum resivoir off a vacuum solenoid, it goes down on passenger side of motor between motor and passenger fender. Make sure you have vacuum there, once you turn it to 4x4 it will apply vacuum for approx 30 seconds then turn off. It will also re-apply vacuum when changing back to 2wd. If you have vacuum at the top connector, check down at both wheels, there will a be a vacuum line to each steering knuckle and check for vacuum there. If you have vacuum at the top connector, none at the bottom then you have a vacuum leak (obviously) pull the line and fix it. (you can tie in wiper hose whereever it is broken, with a couple zap straps)

[gtnit]

get a new switch. the above post is refering to a problem that happens when it is actually trying to/is engaged into the 4x4 but yours soounds like it is not going beyond the switch. one thing you can try is putting 12 volts to the little motor on the transfer case (it is just a reverse polarity motor) and if it engages then you know for sure it is your switch in the dash or at least not getting juiced from it (bad wire in the run). The switches do go out pretty common. I think mine was like $60 or so. Dealer only part

[dieselpower65]

Originally Posted by gtnit

get a new switch. the above post is refering to a problem that happens when it is actually trying to/is engaged into the 4x4 but yours soounds like it is not going beyond the switch. one thing you can try is putting 12 volts to the little motor on the transfer case (it is just a reverse polarity motor) and if it engages then you know for sure it is your switch in the dash or at least not getting juiced from it (bad wire in the run). The switches do go out pretty common. I think mine was like $60 or so. Dealer only part

Well my green light on the back of the 4x4 switch came on and i tried putting it into 4 high but the oarnge lights on the dash never came on and i dont think it engaged, so im still stuck as what the problem could be. and the shaft from the transfer case goin to the front axle spins when i drive.