Hi
My 2003 F150 4X4 has Auto transmission with a manual transfer case shifter.
Heres the problem, recently it felt as though the shifter was shifting but nothing was happening, no light or no 4X4. now It will shift into 4 wheel and out but the light will not go out and the hubs will not disengage. Is there a relay controling these functions, it seems like something is hanging up.
Thanks for your help.

 

Does that truck even HAVE hub locks? I think '97-up F150s use a center disconnect.

 

Thanks Steve I used the wrong term but it is still a problem. The front differential is still engaged with the 4X4 light on dash lit but the transfer case is not engaged. I was wondering what turns the light on and engages the axle. When working properly I could hear a click behind the dash now I hear nothing.
Thanks Again.

 

Sounds like the manual shifter linkage is binding up and not releasing. Once the transfer case locks into 4x4, an elecrical signal is sent to a vacuum relay to lock the Center Axle Disconnect.

Adrianspeeder

 

Thanks Speeder
I have checked the linkage and it moves freely but your vacuum relay sounds more like it, can you give me a hint where to find it.
Thanks Again

 

I'm thinkin you still got a problem electrically before the relay if the light doesn't go out. Perhaps the position switch on the case is messed up.

Adrianspeeder

 

Hey guys,

I would check the switch on the transfer case first like adrianspeeder said, they are bad for getting water contamination and causing it to stick in 4wd or no 4wd. The switch on the transfer case is what tells the Gem module to engage or disengage the frt axle via the vacuum relays. If you un plug the switch and the light goes out it will be the switch that is faulty.

If unplugging the switch does not cure the problem you may have a wiring problem or a gem module problem. Do you have any other electrical problems? I ask because the gem is on the back of the fuse box inside the cab and is know to get wet if your windshield is not perfectly sealed. This causes many erratic electrical problems that seem to come and go at will. I have replaced far too many gem/fuse boxes because of this.

I still think that the transfer case switch is the most likely culprit in your case.

Cya

 

Thanks Explorer I will check that when I get home.
Thanks

 

Mr. Speeder and Mr. Xplorer
Thank You You guys are like geniuses, it was a bad switch that I will change tomorrow. Thanks again for all your help.
Jack