Will this 4x4 Electrical Solution Work??
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Tuned
Joined: Aug 2015
Posts: 383
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Will this 4x4 Electrical Solution Work??
I have had an ongoing electrical gremlin in the ESOF which I can't bowl out. Currently at P1876 and a new solenoid does not appear to be solving the challenge.
Essentially the transfer case is a mechanical box. and the transfer case motor is just a reversible motor.
Given the above, and if we forget ESOF and just shift in neutral when stopped, could you rig a switch in the cab to supply voltage in both directions to the transfer case motor, thereby circumventing the GEM and any sensor related inputs? My theory is you push the switch one way to supply 12 volts and drive the motor until you hear the desired clunks and 4x4 engaged, then release the switch. The same could be done by switching the switch the other way to get out of 4x4.
Cheers
Essentially the transfer case is a mechanical box. and the transfer case motor is just a reversible motor.
Given the above, and if we forget ESOF and just shift in neutral when stopped, could you rig a switch in the cab to supply voltage in both directions to the transfer case motor, thereby circumventing the GEM and any sensor related inputs? My theory is you push the switch one way to supply 12 volts and drive the motor until you hear the desired clunks and 4x4 engaged, then release the switch. The same could be done by switching the switch the other way to get out of 4x4.
Cheers
Elder User
Joined: Sep 2011
Posts: 979
Likes: 4
From: Vancouver
It would be a little more complicated. But yes heavy duty switches would work. Perhaps someone could post a wiring diagram for you to follow. The trick is that there are 2 speed ranges in 4X4, then 2WD and a neutral position in the transfer case. I believe that there are two relays that accomplish this, but I could be wrong.
Are you saying that the transfer case won't shift when you push the buttons?
Are you saying that the transfer case won't shift when you push the buttons?
Thread Starter
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Tuned
Joined: Aug 2015
Posts: 383
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It would be a little more complicated. But yes heavy duty switches would work. Perhaps someone could post a wiring diagram for you to follow. The trick is that there are 2 speed ranges in 4X4, then 2WD and a neutral position in the transfer case. I believe that there are two relays that accomplish this, but I could be wrong.
Are you saying that the transfer case won't shift when you push the buttons?
Are you saying that the transfer case won't shift when you push the buttons?
I was just thinking that given the mechanical nature of the transfer case and the fact it can be shifted with a wrench when required. Why not continue to use the transfer case 12V motor and just run two wires and to the motor by passing everything.
My thoughts were to have a switch that supplies 12V in two directions depending on how its pushed. the 12V would only be for the duration it's pushed. So if one way supplied power to move it from 2W to 4HI then you push until you hear it clunk into 4Hi - it is audible - then release the switch. If you want 4Lo keep pressing until you get the second clunk. Pushing the switch in reverse would provide the same transfers going back to 2wd
Fleet Mechanic
Joined: Nov 2010
Posts: 1,408
Likes: 249
From: Ringgold, Ga
I just learned last week that the two relays under the hood control voltage to tcase motor.
One is for on. The other relay is for off.
Not sure how it determines if high or low is chosen.
One is for on. The other relay is for off.
Not sure how it determines if high or low is chosen.
Laughing Gas
Joined: Oct 2012
Posts: 872
Likes: 18
From: Jasper, Mn
I see no reason why this method wouldn't work. If I were you however I would just use the relays already in place and switch either the power or ground needed to activate them. I would also look at putting in a position indicator just so you and any other drivers know where the transfer case is.
With that being said, have you checked the connector and wires for the encoder? That is where all my issues have been.
With that being said, have you checked the connector and wires for the encoder? That is where all my issues have been.
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Tuned
Joined: Aug 2015
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I see no reason why this method wouldn't work. If I were you however I would just use the relays already in place and switch either the power or ground needed to activate them. I would also look at putting in a position indicator just so you and any other drivers know where the transfer case is.
With that being said, have you checked the connector and wires for the encoder? That is where all my issues have been.
With that being said, have you checked the connector and wires for the encoder? That is where all my issues have been.
Encoder - do you mean the GEM behind the fuse box under the dash? That's where my 4x4 stuff seems to plug in on the side of the GEM about midway down
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Tuned
Joined: Aug 2015
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Hadn't seen that schematic before but relays test out good - guess its possible its wiring under relays - will check again.
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Laughing Gas
Joined: Oct 2012
Posts: 872
Likes: 18
From: Jasper, Mn
Yeah, I know how you feel, Ive gone through hell with this system before too.
The encoder is the plug on the driver side of the shift motor assembly. The encoder tells the GEM what position that transfer case is in. If you are having encoder issues the system won't do anything because it doesn't know what position it is in. Although, I would think that it would throw a code.
The encoder is the plug on the driver side of the shift motor assembly. The encoder tells the GEM what position that transfer case is in. If you are having encoder issues the system won't do anything because it doesn't know what position it is in. Although, I would think that it would throw a code.
Posting Guru
Joined: Sep 2014
Posts: 2,404
Likes: 3
From: Asheville-where weird is
The only issue that I can foresee with the mod is that there is a built-in safety feature that detects speed and therefore prevents the transfer case from shifting into 4Lo unless you are BOTH stopped and in neutral.
Would you be circumventing this safety feature by wiring it this way. Based upon reading the above schematics, GEM, and PCM wiring, I think you would be...but I am not wearing my glasses b/c I lost them, so I could be wrong. Plus, I have no idea how those two communicate with the ABS module, if at all.
Imagine accidentally shifting into 4Lo at 70 mph. Or having someone else do it while they were driving your truck.
You could employ a momentary switch as part one of a two step safety feature: press it to complete the ground for the in cab switches.
Would you be circumventing this safety feature by wiring it this way. Based upon reading the above schematics, GEM, and PCM wiring, I think you would be...but I am not wearing my glasses b/c I lost them, so I could be wrong. Plus, I have no idea how those two communicate with the ABS module, if at all.
Imagine accidentally shifting into 4Lo at 70 mph. Or having someone else do it while they were driving your truck.
You could employ a momentary switch as part one of a two step safety feature: press it to complete the ground for the in cab switches.
Thread Starter
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Tuned
Joined: Aug 2015
Posts: 383
Likes: 0
The only issue that I can foresee with the mod is that there is a built-in safety feature that detects speed and therefore prevents the transfer case from shifting into 4Lo unless you are BOTH stopped and in neutral.
Would you be circumventing this safety feature by wiring it this way. Based upon reading the above schematics, GEM, and PCM wiring, I think you would be...but I am not wearing my glasses b/c I lost them, so I could be wrong. Plus, I have no idea how those two communicate with the ABS module, if at all.
Imagine accidentally shifting into 4Lo at 70 mph. Or having someone else do it while they were driving your truck.
You could employ a momentary switch as part one of a two step safety feature: press it to complete the ground for the in cab switches.
Would you be circumventing this safety feature by wiring it this way. Based upon reading the above schematics, GEM, and PCM wiring, I think you would be...but I am not wearing my glasses b/c I lost them, so I could be wrong. Plus, I have no idea how those two communicate with the ABS module, if at all.
Imagine accidentally shifting into 4Lo at 70 mph. Or having someone else do it while they were driving your truck.
You could employ a momentary switch as part one of a two step safety feature: press it to complete the ground for the in cab switches.
Thread Starter
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Tuned
Joined: Aug 2015
Posts: 383
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Just to close this out a little.
Got the switch and wiring in ready to go - cost $23.
Decided to check fuses and relays once more before I fitted the above.
Bear in mind I had done this already but also decided to empty another can of contact cleaner over the relay box and clean the relays again. Started the truck 4x4 worked once and then wouldn't again. Pulled both relays again and put them back, 4x4 now cycles consistently - until next time it decides to break again
Got the switch and wiring in ready to go - cost $23.
Decided to check fuses and relays once more before I fitted the above.
Bear in mind I had done this already but also decided to empty another can of contact cleaner over the relay box and clean the relays again. Started the truck 4x4 worked once and then wouldn't again. Pulled both relays again and put them back, 4x4 now cycles consistently - until next time it decides to break again
FTE Leadership Emeritus
Joined: May 2014
Posts: 27,344
Likes: 5,941
From: Lake Hartwell, GA
Just to close this out a little.
Got the switch and wiring in ready to go - cost $23.
Decided to check fuses and relays once more before I fitted the above.
Bear in mind I had done this already but also decided to empty another can of contact cleaner over the relay box and clean the relays again. Started the truck 4x4 worked once and then wouldn't again. Pulled both relays again and put them back, 4x4 now cycles consistently - until next time it decides to break again
Got the switch and wiring in ready to go - cost $23.
Decided to check fuses and relays once more before I fitted the above.
Bear in mind I had done this already but also decided to empty another can of contact cleaner over the relay box and clean the relays again. Started the truck 4x4 worked once and then wouldn't again. Pulled both relays again and put them back, 4x4 now cycles consistently - until next time it decides to break again
Cargo Master
Joined: Oct 2010
Posts: 2,089
Likes: 16
If you do go the toggle switch route, i would strongly recommend installing the red switch guards over them that have to be lifted to flip the switch. Just in case so u will not bump them by accident at the wrong time.