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Davo, Master technician
Category: Chevy
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Experience:  ASE Master Technician also L1 Advanced Engine Performance Specialist
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97 chevy truck: K1500..It will not shift into 4-wheel high

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I have a 97 chevy truck, K1500. It will not shift into 4-wheel high. It will shift into 4-wheel low. I have replaced the switch and checked both the fuse for the transfer case and 4-wheel drive. I do not have a schematic for this system and don't know if there are relays in the circuit. I have looked in the fuse box under the hood on the drivers side and found none that seem to have anything to do with 4-wheel drive .
Try this first.Let me know if it works.You may have a shift motor (encoder motor) going bad.
  • Perform the following to clear the diagnostic trouble codes (DTC) and stored memory from the transfer case control module (TCCM) .
  1. Turn the ignition switch to the "OFF" position.
  2. Remove the 20-amp T-case fuse (Number 2).
  3. Wait at least 40 seconds then replace the fuse.
  4. Cycle the ignition switch from "RUN" to "OFF" five times to clear diagnostic trouble code 1 from the TCCM.


  • The codes will not clear if the 20-amp T-case fuse is not removed for at least 30 seconds.
  • Code 1 will continue to occur until the ignition switch is cycled from "RUN" to "OFF" five times.


Customer: replied 8 years ago.
i tried what you suggested, it didn't work. Also, i replaced the shift motor last summer when this problem first occured. In addition, this morning on my way to work, i was running in 2-hi and i noticed the 4-hi light blinking for a time then it stopped. Could this problem be electrical in nature ?

The diagnostic trouble codes are displayed on the three transfer case shift select buttons. The Shift select buttons are located on the instrument panel. When connector pin 13 on the data link cable is grounded, and the ignition switch has been off for at least five seconds prior to positioning the ignition switch to run, the shift select buttons will blink various times together to indicate diagnostic trouble codes from 1 to 4.

  1. Position the ignition switch to "OFF".
    • Ensure the ignition switch is positioned to "OFF" for at least 6 seconds.
  1. Connect pin 13 on the data link cable to a vehicle ground source.
    • The data link connector is located in the cab under the instrument panel on the drivers side.
    • Look for an unplugged cable lead with a connector that is housed by the bottom of the instrument panel trim.
  1. Position the ignition switch to "RUN".
  2. Note the shift select buttons for blinking codes. Refer to DIAGNOSTIC TROUBLE CODES. If the shift select buttons all blink one time and stop, and do not continue blinking, no fault codes are stored in the TCCM. The transfer case shift select buttons will blink to identify any stored DTC. If only one code is stored in the TCCM memory, that code will blind repeatedly with a three second delay between blinking sequences. If more than one code is stored, the first code will blink once, then after a three second delay, the next code will blink. This sequence will continue until pin 13 is no longer grounded. When reading the diagnostic trouble codes, the number of shift select buttons blinking will indicate the code number.


Customer: replied 8 years ago.
If i can retrieve codes from the TCCM, where can i reference the codes ?
Just get the codes I have what they mean and will let you have it or tell you what to check.
Customer: replied 8 years ago.
ok   its cold and dark here now so i may not be able to do it tonite
When you get the chance post your findings here and we will continue.
Customer: replied 8 years ago.
i will
Customer: replied 8 years ago.
ok   got a code 2
here is the flow chart.You will need either a transfer case control module or a shift motor most likely but check the wiring.graphic
Customer: replied 8 years ago.
if i were a tccm, where would i be ?
On the drivers side behind the dash.This a view from the firewall of the truck not the drivers seat.graphic
Davo and 3 other Chevy Specialists are ready to help you
Customer: replied 8 years ago.
Please e-mail your answer, the website is messed up and i can't get to it. E-mail [email protected]    thank you