4wheel drive will not engage, encoder?

Tiny
CRZYDRVR
  • MEMBER
  • 432 POSTS
There could be a problem with the front differential. Put the front wheels in the air and try to turn them in 2wd or 4wd. Check the fluid for metal shavings too.
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Tuesday, May 26th, 2020 AT 6:18 PM (Merged)
Tiny
CUTTOORDER
  • MEMBER
  • 2 POSTS
  • 2000 CHEVROLET SILVERADO
I own a 2000 Silverado Ext. Cab, with 125,000 miles, 5.3L V8. My problem is that the actuator on my transfer case is engaged, even while in 2wd, however the actuator on my front axel is disengaded and works fine. So while I drive down the interstate, the drive shaft from the transfer case to the front axel is spinning, but no power is being put to the front wheels (i did a lot of toying around to make sure that no power was going to them) so im not doing any serious damage to my truck. My question is what would cause the shifter on the transfer case stay engaged? Would this problem be caused by a malfunction of the electronic shifter on the dashboard? And what are some test that I can do to try to narrow down my possible solutions? Thanks a lot for the answers.
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Tuesday, May 26th, 2020 AT 6:18 PM (Merged)
Tiny
JEREL30
  • MEMBER
  • 3 POSTS
I don't actually have an answer. I have a '99 silverado 1500 Z71 stepside. I am having the same isssues. I was just wondering if you found anything out? Any help would be appreciated. And if I find anything out I will look u up.
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Tuesday, May 26th, 2020 AT 6:18 PM (Merged)
Tiny
CUTTOORDER
  • MEMBER
  • 2 POSTS
No I havent fixed the issue yet, but I am going to do some electrical tests to see if the electronic switch on the dashboard is misfunctioning. I have heard that these go bad frequently, so ill give that a shot sometime.
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Tuesday, May 26th, 2020 AT 6:18 PM (Merged)
Tiny
JEREL30
  • MEMBER
  • 3 POSTS
If it is the switch in the dashboard. The truck will deffinatly let u know. A. All the lights go off on the switch. B. Message center will say SERVICE 4WD. But it is an easy fix.
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Tuesday, May 26th, 2020 AT 6:18 PM (Merged)
Tiny
RSKK74
  • MEMBER
  • 1 POST
  • 1999 CHEVROLET SILVERADO
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
Mechanic question. I have a 1999 Silverado 1500 crew cab, good motor. But this 4wd is driving me nuts! I replaced bad dash switch and actuator. I can hear actuator when I push button trying to lock the hubs in, but gives up after third try. And whole dssh switch kicks off and SERVICE 4WD LIGHT comes on in message box Sounds like its half in and half not. Until I push button 2wd three times, then its out of 4wd. Next time I start truck, the 4HI Light is on everytime. Then I have to go through the same ritual all over again. Which I know is hard on the actuator. Anyone have an idea what might be keeping front hubs from locking in? I definitely have power from switch to actuator, then nothing. Thank you for your help!
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Tuesday, May 26th, 2020 AT 6:18 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,606 POSTS
Have it scanned for codes first as it can be a body module problem as well as a connection problem and or the transfer case module. A pro will problably have to do it due to the body module as auto parts can't get those codses
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Tuesday, May 26th, 2020 AT 6:18 PM (Merged)
Tiny
DONNIESUSAN
  • MEMBER
  • 3 POSTS
  • 1996 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
4wd hi button only blinks, keeps blinking, wont go into 4wd. I can hear motor when I press button but front wheels dont engage. Instaled a new USED actuator same result. Is there a way to tell if this a tccm problem, fuse I dont know of (checked #24 4x4), transfer case, switch etc.?
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Tuesday, May 26th, 2020 AT 6:18 PM (Merged)
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Ok we are going to pull codes to see what the codes may be present so we can see what it say's may be wrong with it. So the data link connector (DLC) is near the right side of the steering column. Now you need to make a jumper wire to go from the orange wire or term. number 13 at the DLC and ground. NOw turn key on engine off and watch the 4x4 light on the switch as it will flash codes to you. Now it will flash like a 1 pause 3 seconds and flash like a 3 meaning a 1 and a 3 as all transfer case DTC are single digit. So if you look at the diagram below it shows how it pauses as an example ok. After writing down all codes you will need to turn off the key and pull the 4x4 fuse and now turn the key on engine off 5 times this will clear all the codes from memory.
Now if you look at the graph below it shows what a code 2 will look like and what a code 1 and 3 will look like ok. Let me know what you find.


https://www.2carpros.com/forum/automotive_pictures/249564_Graphic_20.jpg

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Tuesday, May 26th, 2020 AT 6:18 PM (Merged)
Tiny
DONNIESUSAN
  • MEMBER
  • 3 POSTS
OK. Used jumper to connect 13 to 5 (ground?). 2hi light went off when I did so. Turned key off. No code at all.
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Tuesday, May 26th, 2020 AT 6:18 PM (Merged)
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Ok did you do the reset procedure? If not do that just to see if it resets things. If nothing changes then we will have to test the stuff one item at a time.
Now we need to check voltages at TCCM harness (transfer case control module). With key on engine off you need to check for power at the following terminals. Refer to the diagram below ok. C8, C11, C12, C14, D14 and D15. Then check for resistance at C10 to ground it should be 2 ohms or less. If all it good then you will need to pull the 4x4 selector switch out and check for voltage at the pink wire at the switch. If all this is good then we will move to the next step. The diagram below will be needed for that too. Thanks and get back to me.


https://www.2carpros.com/forum/automotive_pictures/249564_Graphic_21.jpg

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Tuesday, May 26th, 2020 AT 6:18 PM (Merged)
Tiny
DONNIESUSAN
  • MEMBER
  • 3 POSTS
I did the reset procedure, I got the 2hi button to blink a code one, with a barely visible light. Not sure if that counts. Also I do not know where the tccm is or what it looks like. So far Ive found a metal box near the steering column 4"x 4"x 2" approximately.
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Tuesday, May 26th, 2020 AT 6:18 PM (Merged)
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
It is under the dash on the steering column support bracket. If this checks out then we will check the transfer case relay. Let me know what you find ok. Thanks.
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Tuesday, May 26th, 2020 AT 6:19 PM (Merged)
Tiny
REDCHEV
  • MEMBER
  • 6 POSTS
  • 1996 CHEVROLET SILVERADO
  • 164,000 MILES
I got a 1996 k1500 with the push botton 4 wheel drive. The front axle actuator has 3 wires. A black ground, a brown wire with ignition power, and a light blue wire thats hot when the 4x4 button is pushed. I tested all 3 wires with a DVOM and the brown wire only has around 3 to 4 volts. I can only find wiring diagrams for the 2 wire actuator. Do you have a diagram I could see? Or any info?
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Tuesday, May 26th, 2020 AT 6:19 PM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
If it is ignition power, then you need to start by checking fuses with a test light. Otherwise, look closely at the harness for breaks.

Roy
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Tuesday, May 26th, 2020 AT 6:19 PM (Merged)
Tiny
REDCHEV
  • MEMBER
  • 6 POSTS
Thats what I want to do. I see on some forums people will post wiring diagrams if someone needs them. Can you do that?
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Tuesday, May 26th, 2020 AT 6:19 PM (Merged)
Tiny
CFERRARO
  • MEMBER
  • 3 POSTS
  • 1995 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 211,500 MILES
I am having trouble with my 4 wheel drive engaging the transfer case engages and the front drive shaft spins but the front wheels don't move. I replaced the actuator and checked for power and all is fine. Does this mean there is something broke in the front axle?
Any help would be appreciated. Thanks
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Tuesday, May 26th, 2020 AT 6:19 PM (Merged)
Tiny
DWB812
  • MECHANIC
  • 108 POSTS
Hi CFerraro,
Just having power at the plug may not be good enough. There is also a ground side to the circuit that has to be good. It's still most likely that the actuator is not engaging the differential. That is what connects the drive shaft rotation into power at the wheels. Did you replace it with a new one or used? Also, do an ohms test or use a test light to be sure the ground is good in that circuit also. Let me know what you find out.
DWB
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Tuesday, May 26th, 2020 AT 6:19 PM (Merged)
Tiny
WILSONJEFFERY6
  • MEMBER
  • 3 POSTS
  • 1990 CHEVROLET SILVERADO
  • 5.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 250 MILES
I've already bought 3 4x4 actuators, it's not a wireing issue, and the most recents one that broke the tip was broken, also I have oversized 35 tires if that has anything to do with it
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Tuesday, May 26th, 2020 AT 6:19 PM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,549 POSTS
Hello,

I don't show an electric actuator for your year truck. Are you installing GM parts, many cheaper units will fail prematurely, the over size tires shouldn't cause the actuator to fail. When you remove the actuator can you inspect inside the transfer case to see if something is causing the problem, I have seen where the engagement fork will break causing the actuator to fail, the transfer case will need to be disassembled and repaired to fix the problem.

Let us know what you find

Best, Ken
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Tuesday, May 26th, 2020 AT 6:19 PM (Merged)

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