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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), GMC Mechanic
Category: GM
Satisfied Customers: 5787
Experience:  GM Grand Master Technician 2007. 14 years experience.
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2005 hummer locked in 4 wheel Both front and rear

Customer Question

2005 hummer locked in 4 wheel hi. Both front and rear differentials will not release. Buttons blink as before. Turns hard.
JA: How many miles are on the car? Has this ever happened before?
Customer: 230,000. No. Went right into 4 wheel when button pushed.
JA: What is the model of your '05 Hummer?
Customer: H2
JA: Are you fixing your H2 yourself? What have you tried so far?
Customer: Just got home. Will check for electrical cause both difs are locked. I dont think 2 actuators can go bad at same time. Is actuator on the transfer case only for high and low?
JA: Anything else you want the mechanic to know before I connect you?
Customer: If electrical, then can I release the posi on thd differentials by feeding 12 volts to the wires when disconnected from the main harness?
Submitted: 10 months ago.
Category: GM
Expert:  Mike S. replied 10 months ago.

Hi, I am Mike, welcome. I'm reviewing your question.

Expert:  Mike S. replied 10 months ago.

Do you have a scan tool?

Customer: replied 10 months ago.
No. Disconnected actuator harness. Checked actuator with 12 volts. Motor turns fine in both directions and releases the front diff. The rear seems to be locked. Hopps on a tight turn. Is there an actuator for the rear? Why wont the button release the front all the way? Does it adjust?
Expert:  Mike S. replied 10 months ago.

When you press any other position on the transfer case switch other than the one it's tuck in now, 4 high, does the switch light flash indicating that the transfer case module has received the signal?

Expert:  Mike S. replied 10 months ago.

As you can see just about any troubleshooting procedure that I have starts out with the use of a scan tool.