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Transfer Case Lights Not Illuminating / 4WD Not Working?

gratata

New Member
Joined
May 20, 2019
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1
I've got a (new to me) 2005 Z71 AV that I bought over the weekend.  I noticed that when I turn the key to the 'Run' position, the windshield wipers come on (if they're engaged) and the instrument panel backlight comes on, but no other lights come on at all.  Everything works as it should when running.  There is no CEL and the only warning displayed is "service airbag".

My main issue is that when I try to engage the 4WD, the transfer case buttons don't illuminate and I don't hear anything moving or engaging and I just want to know where I should start with troubleshooting the 4WD
 
I too am learning about these vehicles as I go but have had similar issue as you have described.
My ECM had lost the ground and needed replacing after I had replaced the encoder ring and motor on the t-case.
You may be able to clean the ground bolts on the body/frame mount just under the front driver door.
There are 2 together on that mount that will get paint and/or corrosion under them.
Hope this helps give a place to start. Good luck to you.
 
gratata said:
I've got a (new to me) 2005 Z71 AV that I bought over the weekend.  I noticed that when I turn the key to the 'Run' position, the windshield wipers come on (if they're engaged) and the instrument panel backlight comes on, but no other lights come on at all.  Everything works as it should when running.  There is no CEL and the only warning displayed is "service airbag".

My main issue is that when I try to engage the 4WD, the transfer case buttons don't illuminate and I don't hear anything moving or engaging and I just want to know where I should start with troubleshooting the 4WD
Start with fuses.  ATC in underhood fusebox and 4WD in dash fusebox.
 
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