Question about 1997 Chevrolet Blazer

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I have a 97 blazer 4wd i repalced vaccum switch all vaccum lines and made sure actuator cable was good lights come on like im in 4wd but diff doesnt lock in and actuator not getting vaccum

Should you be able to move the actuator cable by pushing on the actuator with your fingers.mine will not squeeze if i push on it

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The vacuum actuator should move by hand without vacuum applied. You should also be able to see it move if you have someone switch the transfer case into 4hi/lo from 2wd and then back again. There is a vacuum switch on top of the transfer case that locks vacuum once the encoder motor engages the transfer case to lock the front axle into position, and then releases the vacuum once the encoder switches back into 2wd mode allowing the front axle to decouple. If you aren't getting vacuum, first check your vacuum lines for leaks, then check for vacuum coming from the transfer case when it's in 2wd mode.

Posted on May 08, 2014


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Posted on Jan 02, 2017

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SOURCE: 4wd not engaging

These trucks are famous for the transfer case control module failing
and causing problems like you are experiencing. The module is
usually located in the passenger foot well kick panel. You should
be able to find it easy since that is what is making the clicking noise
when you try to go into 4x4. When you find it-unplug the 2 connectors
and looks for green corrosion on the terminals in the plug and also on
the module. They are famous for water intrusion thru the heater system. If you find corrosion, terminals in the connectors will need to
be replaced as well as a new module(they are expensive).

Posted on Dec 14, 2008

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SOURCE: repalce ball joints 01' Chevy Blazer 4WD

you should just be able to loosen the half shaft and be ok that way

Posted on Mar 09, 2009

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SOURCE: 2000 Blazer stuck in 4WD

The first thing I would look at is the shift rod on the transfer case. If I remember correctly, it is on the drivers side and is a rod aboutsix inches long and has two ends that basically pop into rubber gromets. If that rod is bent in any way, or has come loose of the gromets, it will not shift into or out of the four wheel drive. If yours has electronic four wheel drive, the electric acutator could be out or going out. you should be able to remove the rod and simply move the switch by hand on the transfer case. It will get you out of 4 wheel drive until you have the ime to diagnose the electronics at least. It has happened to both my 1994 and 1999 S-10 blazers.

Posted on Apr 21, 2009

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SOURCE: 1997 chevy blazer. when I push the 4wd button, it

Check the fuse to the 4x4, if the fuse is good then check the 4x4 electric motor actuator on the transfer case. You should hear it work from 2wd, 4hi to 4low and back to 2wd with the push of the switch. if you don't hear it working then check the wire harness at the actuator motor, look for any damages like corrosion or cracked wire connector clips. If all electrical is in good working order, replace the actuator motor. If the 4x4 actuator is working on the transfer case, then the front hub 4x4 actuator may have gone bad and that's located on the front differential. It's common for the clip there to corrode and break and is an easy fix with a new collar pin, at worst it's the diaphragm on the vacuum actuator that is located under the battery tray. There is a vacuum switch on the top of the transfer case, driver side but when that fails, your front hub stay's locked in the on position. Good luck and keep me posted and hope it's a simple fuse that has gone bad. You can pick up all these parts at Auto Zone or Parts Source and they will have the step by step instructions for you to get the job done with common tools.

Posted on Dec 15, 2009

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SOURCE: My 1999 chevy silverado 1500 four wheel drive

You probably have a bad encoder motor.It is located on the side of the transfer case on the drivers side.It is black.The other problem they had with these was the switch but you have already replaced this so your next thing is the encoder motor.Hope this helps.Good luck.

Posted on Dec 28, 2009

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1 Answer

Frontend wont lock in 97 blazer.?

Front end lock is vacuum actuated and if there is no vacuum from the shifter switch, it will not lock the front end. Make sure there is vacuum going down to the switch/valve on the shifter with it in 4wd and engine running, then find if there is vacuum coming out the other side of the switch on the tranny shift valve. On the right fender you will find the cable pull that the vacuum actuates to pull cable and put the front end in gear. Have someone watch while you shift into 4wd to see if the cable is pulled. Check there to see if there is vacuum coming to it when in gear. If there is no vacuum there then the shifter vacuum switch is bad or the line is not connected.

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There is a Vacuum switch that is on top of the transfer case that will send vac to a actuator located unber the battery when put in 4WD. I would make sure it's getting vaccum and also make sure battery acid hasn't leaked down on to the actuator and cable that goes to the front diff.

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Transfercase engages but hubs will not lock 97 s-10

This is a difficult problem to solve without trouble shooting alot of things. There is sometimes a electrical relay for the locking hubs test it. Also sometimes you have to be able to back up to engage/disengage the hubs. Make sure your transfer case is full of the proper oil and that the driveshafts are not loose at all. If all of these items work properly and the hubs will not engage still i would suggest checking into a repair shop and finding out the cost of hub replacement. Then check with your local parts store and find out the price of new hubs and a Haynes manual. The manual can walk you through step by step on item location and repair techniques.

Apr 07, 2010 | 1997 Chevrolet Blazer

1 Answer

My 1999 chevy blazer 4wd just quick working it engages but doesnt work? please help need answer fast

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1 Answer

When I push the 4 wheel drive buttion . The light flashes but will not go in 4 wheel drive

Check to see if the front diff is being engaged. Ther is a vac switch that come from the transfer case. It sits right on top has 3 lines. One line is vac input the other is vac output the third is a vent. When you push the 4wd button that switch allows the vac to the front diff. The front diff actuator is under the battery. Check to see if the actuator is moving if not check to see if the switch is any good by checking vac on the actutor line. You can doo this with out taking out the battery. You will see a line that goes from the back of the engine up the right side then under the batt. It is covered by wire loom. Cut in to it and see if there is vac. If not check to see the switch works. If there is then check to see if the actuator is torn( actuator looks like a cruse control actuator) or the cable to the front diff is stuck.

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My 2000 blazer won,t select 4wd hi/low or auto

there is a vacuum solonoid on the firewall in the middle with 2 vac lines and a 2 wire plug
thats ur problem
push the button and smack it with the handle of a screwdriver should work

Feb 02, 2009 | 2001 Chevrolet Blazer

1 Answer


the actuator is under the battery
if the little light comes on then u probly have to adjust the cable
there is an adjusting nut around the cable where it goes into the diff

Jan 02, 2009 | 1999 Chevrolet Blazer

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1999 chev blazer 4x4 system

I have a 1999 chevy blazer that stuck in 4 wheel drive. How do you get it out.

Nov 23, 2008 | 1999 Chevrolet Blazer

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4x4 on a 2001 s10

when the transfer case shifts into 4wd it activates a vaccum switch on the transfer case which sends vaccum to the accuator for the front axle. the accuator pulls a cable that locks in the axle. the switch on the transfer case is a well known problem. check for vaccum in and out of this switch in 4wd. if you have vaccum out then check the accuator under the battery. If the vaccum switch on the transfer case is bad you can find one at most parts store in the HELP section #49315. please rate if this helps

Nov 22, 2008 | 2001 Chevrolet S-10

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