As previously stated, my 4x4 high will not engage, 4L will. I can actually hear it engaging and the light stays on. When I put it to 4H I can hear clicking in the dash but nothing. I purchased a new transfer case motor. Here is what i found out.

1) there was a black wire coming out of the transfer case, I'm guassing a ground wire? I just cut it since the new motor has an extra pin in it in the same location. Other than that all the pins were the same and everything bolted up nicely. Since i drive this daily, will that black wire need to be hooked up or can I just secure it and tape it off? I wasn't sure what it controlled but looked to be a ground. Let me know if it's an important wire I wont drive it tomorrow.

2)same thing NO 4H but 4L will work.

3) I took the new motor off and had someone put it in the 2H and 4H and 4L, the motor moved on all the parts except 4H. It didn't move at all. Like the motor was not getting any power to move it to 4H.

so am I looking at an electrical issue ? What's next to check?

Since I can move it to 4L, I wouldn't think a fuse, I checked the fuses that I would think controls those, but I'm open to all suggestion. It's really weird and I'd like to get this fixed.

Thanks,

 

That black wire coming out of the transfer case is the power wire to the clutch solenoid inside the transfer case. You'll need this if you want to shift on the fly...it powers up the coil which will spin the front drivetrain to match the rear drivetrain speed before the shift fork will engage the dogs for the front drive. Big noise and eventually lots of little ground up chunks of metal in the case if you don't hook it up and shift into 4 while moving. You should be able to shift into 4 at a stop without that coil though.

It'll be fine unhooked as long as you don't try to shift into 4 until you get another chance to work on it.


If it's doing 2Hi and 4Lo, but not 4Hi then I'd suspect the GEM isn't working properly. I don't have my service manual handy...will have it again tomorrow and can post more unless someone else can help you out in the meantime.

 

since the new motor didn't have the black wire, is there a wire I need to splice it into on the new motor?

GEM not working correctly, I dont like the sounds of that.....it sounds expensive

 

I'll try and see if I can remove the On the fly switch, perhaps wire came loose or something. Previous owner put in an aftermarket head unit and perhaps the wire got knocked loose or something.

Bud since I'm hearing clicking noices when put in 4H I wouldn't suspect the selector a cable issue.

If I can hear the clicking, is that the sound after the GEM receives the signal?

 

Are you getting any codes set because things aren't shifting properly? That would help pinpoint down to what might be the trouble.

I haven't had to dig into the electrical end of my truck's 4wd yet so I'm not real sure on the specifics of it.
There should be relays for the front axle engage and disengage, one relay for the electric clutch, and I believe two relays for the shift motor (one for clockwise movement and the other for counterclockwise).

The relays for the shift motor are used for all three shifts...2H, 4H, and 4L so they should be working if you can shift into 4L.

The shift selector switch is actually a potentiometer...each position has a different resistance reading. this is how it tells the GEM which position you're trying to select.
2H, the switch should measure 3900ohms plus/minus 200.
4H, it should measure 1000ohms plus/minus 50.
4L, it should measure 360ohms plus/minus 20.


The GEM recieves the signal from the shift selector switch and cycles the proper relays to go to each position. Your truck sounds like its just not trying to go to 4H at all and that seems to me that the GEM either isn't getting the right signal to start the shift or it isn't sending the right outputs to start the shift.

Hope this helps!

 

Oh, on that black wire for the electric shift coil in the transfer case...

You'll have to pull the pin for it from the old shift motor connector and insert it into the new motor's connector. To do this, look at the front of the connector and find the little red piece of plastic in between the pins. This is a lock piece and can be removed by pulling it straight out the frint of the connector with a needle-nose plier. Next, behind that locking piece each pin hs a small snap catch holding the pin in. Use a small screwdriver to gently pry that catch up and then pull the wire and in out the back of the connector. To insert the pin into the new connector, just remove that locking piece and push the pin/wire through the back into it's appropriate hole. Replace the locking piece and you're all set...just splice the wire back together where you cut it and seal the splice up with some of that liquid electric tape gunk to waterproof it.

 

What causes the the clicking sound I hear when I put it in 4H?
is that the relay or is that the GEM? I'm going to try and measure and see what I can get. Would I be able to trace the wires to the GEM and see if there is anything visual or loose for connection? Between the GEM and the transfer case motor, do you think there are relays/fuses inline? Perhaps it's just not making it there?

As for trouble codes, I dont have the check engine light on....I did, but it was EGR and lean in bank 1/2 related. Other than that nothing.

The light does not come on for 4H, only for 4L. I can however hear clicking sounds but the light never comes on and the clicking does not go away from what I can tell.

This really sucks because most of the thread I have found is 4L not working so searching hasn't gotten me very far.

Thanks for trying to help...I'll see if I can pinpoint some wiring.

 

I'll take a look, but if I remember, there is a wire from the new motor using the pin already. It goes from the blue part to the harness.

I'll look again.

Thanks again.

 

The clicking that you hear is the relays themselves. Two relays are for the shift motor (mounted on one module according to the FSM), another relay mounted separately is for the electronic clutch. According to the only schematic I've got (the vacuum diagram for the front drive), the front drive lock/unlock solenoids are driven directly by the GEM (no relays).

I don't have the electric troubleshooting manual and the FSM doesn't give the location of them. Might need to stick your head under the dash to narrow down where they're at.

It is possible that you've got a broken wire somewhere...but that doesn't make sense to me since the same wires run the shift motor for the 4H shift as well.

Shoot me an email to mapeATcsicable.net . I'll send you a little more detailed info on the pinpoint tests tomorrow morning after work. (They're kinda long to sum up in a post here.)

 

I haven't had time to run those test you posted yet, but here is something else i have noticed that might or might not help diagnose the issue or atleast where to start.

Usually when I start the truck all the lights come on (4x4 low, etc....), well couple days ago I noticed there is another spot on the day next to the 4x4 like AWD or something. That light never comes on. Is that the 4x4High? It never illuminates like the 4x4 low does.

Perhaps it's not suppose to....just thought I'd post that up.
I wasn't sure if there is a different light that turns on for 4x4 high vs 4x4 low. Or does the low part just light up when it's in low and only displays 4x4 when in high? I wasn't sure what that other spot could be to light up for.

Thanks,

 

When 4 high pops on (and the computer is aware of said fact-personal experiance issue) the 4X4 light illuminates. When it goes into low range the 'Low Range' light illuminates. Often a semi generic parts are used with extra bit or capibilities for other lights. Though i am not sure what is next to the 4x4 off hand.

 

I wasn't sure if that light is ment for 4x4 high or just there so the gauge cluster can be used through out several vehicles.

It has something like *AWD if I remember correctly.

I guess that has nothing to do or will not help solve my issue...back to testing.

 

That spot where there should be an AWD lamp is only used in the "auto-shift" 4x4 models. (I've only seen it in Expys, but I think it was optional on the F150s too)
If your selector switch doesn't have an AUTO position, then no need to worry about that one.

In a regular electric-shift, you should have one lamp that lights up "4x4" to indicate that you're in 4Hi. Both that "4x4" lamp and the "Low Range" lamp should be lit when you're in 4Lo.

 

OK----yea mine both light up when in 4L.....I'll get back to testing why the 4H is not and report back with what I found out. Such a strange thing.

I know you mentioned you didn't have the wiring diagram. Does anyone know if there is a certain wire for just 4H? I was thinking maybe it's the harness that you plug the TC motor's harness into. The black thing perhaps no good connection. Since there are 7+ pins I think it was its a bit hard to trouble shoot. I'll see what I can find out one day this week though.

Thanks again.

 

so I got a new switch from Autozone. They only had one switch available. The new switched hooked up fine to the wiring but did not fit in the plastic case. There was a small nipple that did not match up to the factory one. There is a small hole that it sits in. Either way I also noticed the new selector switch had 4 settings. When i moved it over one it did the same thing just clicking in the dash click, click, click, when I move it again the 4x4 light comes on. No LOW though. One more turn now the LOW sign come one.

I kept it in the 3rd position for a while to see if the low light would come on but it did not. I went below and the half shat was in deed locked.

At this point I was sure it was the switch and went to the dealer and got the right switch ordered.

Got it today, back to square one. the new switch does the same thing the old factory one did. Click click click click when in 4H, this switch fit perfectly and only has 3 settings.

Any thoughts what to check next? At this point to me seems like not enouph voltage but why would the 4 position switch selector engage 4x4 high and not the 3?