wheel drive button, which should flash for at least 20-30, which does not

2002 CHEVROLET BLAZER
170,000 MILES • 4.3L • 6 CYL • 4WD • AUTOMATIC
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JOE THE MARINE
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When I want to switch to four wheel drive, I but it in neutral, press the four wheel drive button, which should flash for at least 20-30, which does not , I believe its not in four wheel because I don't hear it engage. If I do it in the 4 low drive switch, I can hear it bang and engage. I cannot know if its it four wheel. I tried it in the 2-4 inches of snow we had today and I was slipping and sliding all over the place and the rear tires where spinning. Do I need a new four wheel drive switch? i am stuck on this issue.
Jan 13, 2019 at 6:01 AM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.
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ASEMASTER6371
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Good morning,

It is possible but all the switch does is send a signal to the module for which position the motor on the transfer case.

I attached a diagram for you to view. You need to check for power to the motor when commanding four wheel drive.

Roy
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May 14, 2021 at 12:28 PM
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JOE THE MARINE
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Should I check the fuses under the hood and see if it is blown first? is the module the one on the dash you are talking about? or is there one on the transfer case I can check out?
May 14, 2021 at 12:28 PM
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ASEMASTER6371
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Yes, check both fuses listed for power on both sides with the key on.

The module is right behind the right side kick panel by the glove box.

Roy
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May 14, 2021 at 12:28 PM
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JOE THE MARINE
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is there any way too check if the module is bad?
May 14, 2021 at 12:28 PM
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ASEMASTER6371
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By verifying inputs and outputs.

You would need a scan tool that can monitor the four wheel drive module and watch for signal being sent.

Do you have a scan tool? If you do not, I suggest you at least have someone check it for you. Once they determine the failure, you can do the repair.

Roy
May 14, 2021 at 12:28 PM
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JOE THE MARINE
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Would a obd2 Code Reader be helpful for this?
May 14, 2021 at 12:28 PM
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ASEMASTER6371
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No, you need a real scan tool that can access all the modules.

Roy
May 14, 2021 at 12:28 PM