# 2 transfer case fuse blows and 4X4 does not work?

Tiny
NPROM961
  • MEMBER
  • 2000 CHEVROLET TAHOE
  • 5.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
The SUV listed above is a z71. 4x4 doesn't work original fault said c0323 for transfer case lock circuit low. The previous owner mentioned going through multiple transfer case motor when he had it. Replaced transfer case motor and when I would go to shift into 4x4 it would blow the #2 20-amp fuse. Started diagnosing and found no power on orange wire for 4 pin connection to transfer case motor traced back to plug at firewall and found plug full of corrosion. Replaced plug with weather pack and had power at orange wire and fault went away. Still blew the fuse. Did a resistance test across wires to transfer case motor to plugs at firewall all ohmed out good except tan wire for lock solenoid control. Ran an overlay wire for tan wire and spliced it in. Tested new wire and ohmed out good. Around this time the fuse started blowing immediately when I put a new fuse in. The next day started diagnosing again with no issues, then starting blowing the fuse all the time again. Kind of at a loss right now on where to go next.
Sunday, February 19th, 2023 AT 10:17 PM

6 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 51,582 POSTS
It sounds like the front actuator/switch has shorted out, but to be sure please unplug the actuator to see if the fuse still blows. Here is the location of the actuator and I have included the 4x4 system wiring diagrams so you can see how the system works. Please let me know what happens.
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Monday, February 20th, 2023 AT 12:08 PM
Tiny
NPROM961
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  • 4 POSTS
I unplugged the actuator, and it still blows the fuse. The wiring diagram for the 4x4 system seems slightly different from what I have. The wires to my front actuator are brown, black/white, black and gray/black.
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Monday, February 20th, 2023 AT 5:55 PM
Tiny
NPROM961
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  • 4 POSTS
I can test the function of my actuator with the scanner I have and watch it go in/out. The only time I can find that it doesn't blow the fuse is when the 6 wire plug on the transfer case motor is unplugged, but this is the only new part I have put on.
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Monday, February 20th, 2023 AT 6:08 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 51,582 POSTS
I would remove the transfer case actuator and leave the wires connected to see if the actuator moves without blowing the fuse. You may have an internal problem with the transfer case.
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Tuesday, February 21st, 2023 AT 8:31 AM
Tiny
NPROM961
  • MEMBER
  • 4 POSTS
I removed the transfer case motor and left wires attached did not move. Returned the new one I had bought for another replacement. Plugged in and this time no blown fuse and it moved when buttons were pushed. Put it all back together and drove it a little bit and now have a fault for U1026.
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Tuesday, February 21st, 2023 AT 5:34 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 51,582 POSTS
The U1026 code for a 2000 Chevrolet Tahoe refers to a communication problem with the Transmission Control Module (TCM) or the Engine Control Module (ECM). This code means that there is a loss of communication between the TCM or ECM and the rest of the vehicle's systems. Possible causes for this code include a faulty TCM or ECM. If the transfer case works please start a new question for the new issue
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Thursday, February 23rd, 2023 AT 11:39 AM

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