Stuck in 4 low

Tiny
SHADOWSTRYDER
  • MEMBER
  • 2001 CHEVROLET BLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 110,000 MILES
My Blazer is stuck in 4 low. If I push the button for 2 wheel it flashes then goes back to 4 low. I have checked the relay wiring and also have disconnected the negative cables to try and reset computer. No luck. I was told that the majority of the time it is the actuator as they have a history of going out before the vacuum switch. Is there a way to tell which it is without having to spend 70 bucks for a diagnostics. Or is there possibly a fuse?

Thanks
Don
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Tuesday, May 11th, 2010 AT 11:36 AM

41 Replies

Tiny
BMRFIXIT
  • EXPERT
The transfer case encoder go out on these trucks but to be sure here is the wiring diagrams and a guide so you can check for power and ground to confirm the failure.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

It might be the controller.

Check out the diagrams (Below). Please let us know what happens. Cheers,
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Tuesday, May 11th, 2010 AT 9:36 PM
Tiny
SHADOWSTRYDER
  • MEMBER
Yep it was the encoder motor it took me about an hour to install and cost me $145.00 all fixed! I love this site.
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Tuesday, May 11th, 2010 AT 9:41 PM
Tiny
BMRFIXIT
  • EXPERT
Good to hear, please use 2CarPros anytime we are here to help.

Cheers
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Wednesday, May 12th, 2010 AT 6:06 AM
Tiny
CHEVTRUCKJ
  • MEMBER
  • 2001 CHEVROLET BLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 245,000 MILES
Stuck in 4 wheel low. How can I get it out
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Monday, November 19th, 2018 AT 6:14 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
DO you have the electric shift or shifter on the floor?
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Monday, November 19th, 2018 AT 6:14 PM (Merged)
Tiny
AANTIJUNTI
  • MEMBER
  • 2001 CHEVROLET BLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 132,000 MILES
When I start my car the 4 wheel drive swithes will blink, then the car will swith into 4-low. Ill swith it back to 2 hi but while driving it will occasionaly start to blink (4low)and if I come to a stop and put in (Nuteral ot Park) it will switch in 4- low again
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Monday, November 19th, 2018 AT 6:14 PM (Merged)
Tiny
FACTORYJACK
  • EXPERT
Do all the lights blink, when this is happening, or just the four low indicator. Is there something that splashed on the switch panel, and perhaps is causing it to stick. It sounds like a fault with the switch, and it changes range, because park or neutral and 0 speed, meets the criteria for it to shift.
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Monday, November 19th, 2018 AT 6:14 PM (Merged)
Tiny
BOMBADEE
  • MEMBER
  • 2001 CHEVROLET BLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 108,000 MILES
My blazer shifts from 2hi to either 4 hi or 4 lo with narry a problem but
when shifting from either back to 2 hi it will take upwards of 20 minutes. This occurrs whether the car is moving or standing still in or out of gear.
Anybody got any ideas?
Carl
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Monday, November 19th, 2018 AT 6:14 PM (Merged)
Tiny
RHALL77
  • MEMBER
Do the lights on the control switch blink when it is trying to go back into 2wd.
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Monday, November 19th, 2018 AT 6:14 PM (Merged)
Tiny
BOMBADEE
  • MEMBER
The lights on the control panel will blink at times and other times they will not.
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Monday, November 19th, 2018 AT 6:14 PM (Merged)
Tiny
BOMBADEE
  • MEMBER
Also they are totally out quite a lot of the time even when in 2 hi and the car is being driven normally
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Monday, November 19th, 2018 AT 6:14 PM (Merged)
Tiny
RHALL77
  • MEMBER
Sounds like the automatic transfer case module is bad and needs to be replaced or a possible switch
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Monday, November 19th, 2018 AT 6:14 PM (Merged)
Tiny
BOMBADEE
  • MEMBER
Are these big buck items?
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Monday, November 19th, 2018 AT 6:14 PM (Merged)
Tiny
RHALL77
  • MEMBER
Not to bad, but I ould have the vehicle scanned and check for codes in that system
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Monday, November 19th, 2018 AT 6:14 PM (Merged)
Tiny
FENDERGUY
  • MEMBER
  • 2001 CHEVROLET BLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 70,000 MILES
My 4 wheel drive indicator lights just flash when trying to shift out of 2HI into 4LO, 2LO or Auto 4 wheel Drive. The lights will continue to flash until I push the 2HI button, then the flashing lights stop and the 2HI light is on. I usually can hear a noise at the rear of the car and I notice the RPM gauge reads higher at the same speed while the lights are flashing. I do know the front tires are not engaged, because I viewed them while I was stuck and the 4 wheel light was flashing. I know I must have the transmission in neutral to shift to 4LO. The blazer was not used for about 2 weeks just before this problem started, also the check engine light came on after the idle period for about 2 weeks and then one day when I stated it and it was off. I have checked the transfer case and the panel light fuses.
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Monday, November 19th, 2018 AT 6:14 PM (Merged)
Tiny
JACK42
  • MEMBER
Try this to see if it has stored any trouble codes
BLAZER T-CASE SELF DIAGNOSTIC - Turn ignition for at least 6 seconds. Locate DLC ( diagnostic connector) near right side of steering column. Install jumper wire from pin #13 (orange wire, labels are small but they are on connector, use flashlight) to ground. Turn key on, engine off. Observe shift select buttons. If they all blink once at the same time there are no trouble codes. Otherwise the light will blink (codes are 1-4 flashes) with a 3 second delay between codes if there are more than 1. Run the codes and get back to me with what you find
Also might want to have the PCM scanned to see what the light was on for, it may have something to do with it
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Monday, November 19th, 2018 AT 6:14 PM (Merged)
Tiny
CORVETTE2@COX.NET
  • MEMBER
  • 2001 CHEVROLET BLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 105,000 MILES
Transfer case will go into 4lo from 2hi on its own. This occurs after a brief run on open road and coming to a stop. It does not mater whether it is n drive neutral or park, after some fussing with the buttons it will go back to 2hi. It is a np236, auto or pushbutton select style. Drained oil and check for metal and debris, found none. Replaced with the gm fluid. Can hear the motor and forks engage when assistant pushes buttons. Removed motor and manually shifted stub shaft, it solidly engages the ranges and doesnt feel loose. Checked connection and inspected wires for damage. Pulled atc computer out and found corrosion on 2 pins in the computer termination plug and corrosion on the power supply plug on one pin. Cleaned thourghly and reassembled. It actually made the problem occur consistently. Inspected dash switch, nothing obvious and it does function. I have read every idea I can on the internet and gone over the pieces many times. In ther driveway with an assistant pushing the buttons it will shift and stay and have even put in the air and live tested it. Back on the road however the problem is consistent. Any help is greatly apreciated. Thank you Mark Guin
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Monday, November 19th, 2018 AT 6:14 PM (Merged)
Tiny
DENNYP
  • EXPERT
If you found corrosion in the transfer case control module, you need to replace it.
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Monday, November 19th, 2018 AT 6:14 PM (Merged)
Tiny
JOE1234
  • MEMBER
  • 2001 CHEVROLET BLAZER
Drive Train Axles Bearings problem
2001 Chevy Blazer 6 cyl Four Wheel Drive Automatic 114k miles

truck goes into 4 whl lo lit blinks all the time trying to shift into 4 whl-lo
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Monday, November 19th, 2018 AT 6:14 PM (Merged)
Tiny
LOUT5369
  • MEMBER
You know you can't shift into four low with the truck moving, you have to stop put the truck in neutral then hit 4 low button. Try that
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Monday, November 19th, 2018 AT 6:14 PM (Merged)

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