RobsF150

My buddy has a 2001 f150, and recently the 4wd stopped working. When you switch it into either 4wd hi or 4wd lo the indicator light on the dash does not come on, nor do you hear any sounds like the 4 wheel drive has engaged. We recently replaced the heater core on the truck, and it was shortly after that the 4wd stopped working, not sure if maybe theres something we looked over putting the dash back together?? Any help would be much appreciated, as New England winter is coming, and 4wd would be great. Thanks alot

OldSchoolFordMan

Got the same issue except I didn't touch anything under the dash. It just quit - no indicator light, no 4wd. Checked fuses #5, 11, 29, 30 and 111 all good. Beginning to think it may have something to do with the switch itself.

carbon

I am having the same problem. Was told to check the vacuum lines that go from the fire wall to the front diff for leaks. I also just replaced the solenoid on the back of the transfer case and still the same thing. Would these lines cause the no lights and no sound to occur?

Troupe

i wouldnt think that the vacum lines would cause no light on the dash sounds like a fuse blown or either the switch is bad. do you have a way to test the switch? that might be a start of either check the fuses that has any little think to do with the truck. Or try reseting the computer that might fix it to

carbon

All fuses are good and as far as I can tell the switch is good as well.

Troupe

might wanna try resetting the coputer just for shi*s and giggles you know what i mean alot of times that helps

carbon

The vacuum lines were melted through from coming in contact with the exhaust manifold so those have to be replaced before I can further diagnose the problem.

RobsF150

i checked all fuses related to the 4wd and they look good. and there is power getting to the switch, so maybe it is a faulty switch???

RanchWood

i would check if your getting power to the motor that engages the 4X4 mine went out and there was no go but i swapped it out for a new one and it was ready to roll same thing happened on my 01 f150 and my dads explorer you can pull codes on it and it will tell you if its that before goin and buying one

Bret4207

I have the same issue on a 97 150. I checked the vacuum motor on the front ax and it works fine. But on the right side fire wall where the 2 sets of vacuum lines connect to the "manifold" (? what do you call it?) I only get vacuum to one side. Shifting to 4wd does nothing. Where should I check next? And what do the previously mentioned fuses activate?