4x4 not working help!!
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4x4 not working help!!
Ok i have a 01 f-250 7.3 6 speed. I bought the truck a few days ago and the 4x4 wasn't working the dealer replaced the transfercase motor. I have another 01 f-250 that i have been switching parts out of to see if that makes a differences and found nothing to work. Ive switched the switch on the dash out and nothing. Ive switched the two relays under the hood and nothing. I have also checked all fuses. and the connectors on the transfer case. So i finally popped the covers off the two relays and squeezed them with my fingers and boom transfer case locked into 4lo and then i can squeezed the other and boom back in 2h! So now i'm lost i know the wiring from the relays to the transfercase is good and the switch is good and relays are good so i'm at a loss.. any help would be awesome! also cruise control isn't working idk if that could be related i don't think it is but idk?
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The GEM applies ground to pin #86 on the relays to activate the relay. If your switch and all the rest of your wiring is ok, then possibly a bad GEM.
Do you have any warning lights on? ABS, Engine?? I am not familiar enough with your year model, but sometimes an unrelated trouble code may disable the 4x4 and even the cruise control. The GEM sometimes disables non essential systems in order to protect the driveability of the truck and engine when certain troubles are detected. If you have any warning lights on, check the DTCs first.
On 2002+ models, I know a shared item with the cruise control and the transfer case is the brake pedal switch. Not sure if that is the same on 2001?
Do you have any warning lights on? ABS, Engine?? I am not familiar enough with your year model, but sometimes an unrelated trouble code may disable the 4x4 and even the cruise control. The GEM sometimes disables non essential systems in order to protect the driveability of the truck and engine when certain troubles are detected. If you have any warning lights on, check the DTCs first.
On 2002+ models, I know a shared item with the cruise control and the transfer case is the brake pedal switch. Not sure if that is the same on 2001?
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They came out of my other truck and the 4x4 works on it! What ever sends the signal to the relays ain't working!
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The GEM applies ground to pin #86 on the relays to activate the relay. If your switch and all the rest of your wiring is ok, then possibly a bad GEM.
Do you have any warning lights on? ABS, Engine?? I am not familiar enough with your year model, but sometimes an unrelated trouble code may disable the 4x4 and even the cruise control. The GEM sometimes disables non essential systems in order to protect the driveability of the truck and engine when certain troubles are detected. If you have any warning lights on, check the DTCs first.
On 2002+ models, I know a shared item with the cruise control and the transfer case is the brake pedal switch. Not sure if that is the same on 2001?
Do you have any warning lights on? ABS, Engine?? I am not familiar enough with your year model, but sometimes an unrelated trouble code may disable the 4x4 and even the cruise control. The GEM sometimes disables non essential systems in order to protect the driveability of the truck and engine when certain troubles are detected. If you have any warning lights on, check the DTCs first.
On 2002+ models, I know a shared item with the cruise control and the transfer case is the brake pedal switch. Not sure if that is the same on 2001?
Ok thanks where is the GEM if I find it and get a diagram I maybe able to shoot out some wires!
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According to the diagram, circuit 781 and 782 are going to be your signal leads to the relays. The GEM applies ground to activate the relay. If you were desperate, IMO, you could also just wire in your own switches by removing the 781 and 782 wires from the gem and wire each one up to a toggle switch to ground. This would activate the relay whenever the toggle completes the ground circuit. Do this at your own risk. You would also have to put manual locking hubs because the vacuum to auto hubs is not a simple on/off and requires timed vacuum to work.
Last edited by erikkloss; Jan 12, 2017 at 10:46 AM. Reason: more info
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The GEM (generic electronic module) is essentially the body control computer. It is located behind the fuse panel under the dash. I provided you a link earlier to a page with the wiring diagram. If you try and swap the GEM with your other truck, it may or may not work because the GEM is programmed to match the options of the truck.
According to the diagram, circuit 781 and 782 are going to be your signal leads to the relays. The GEM applies ground to activate the relay. If you were desperate, IMO, you could also just wire in your own switches by removing the 781 and 782 wires from the gem and wire each one up to a toggle switch to ground. This would activate the relay whenever the toggle completes the ground circuit. Do this at your own risk. You would also have to put manual locking hubs because the vacuum to auto hubs is not a simple on/off and requires timed vacuum to work.
According to the diagram, circuit 781 and 782 are going to be your signal leads to the relays. The GEM applies ground to activate the relay. If you were desperate, IMO, you could also just wire in your own switches by removing the 781 and 782 wires from the gem and wire each one up to a toggle switch to ground. This would activate the relay whenever the toggle completes the ground circuit. Do this at your own risk. You would also have to put manual locking hubs because the vacuum to auto hubs is not a simple on/off and requires timed vacuum to work.
Heck yea man I didn't see the link last time that will help out a lot I'll be able to shoot those wires and hopefully find the problem! And yea I kinda knew you would hook a ground to the relay and run it to a switch but I wasn't sure the details on weather to leave the switch on or just long enough to activate the 4x4 then switch it back off!
Thanks a lot for your help I'll get back on here and let you know what I find once I get the time to look into it!
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