4x4 not working

1999 CHEVROLET TAHOE
149,573 MILES • V8 • 4WD • AUTOMATIC
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JASON LOCK
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transfer case fuse blows when inserted when i unplug actuator on transfer case fuse does not blow should the front driveshaft turn freely when truck is in park 4x4 does not work
Feb 28, 2009 at 2:06 PM
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RACEFAN966
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Ok first I need to know if you are up to doing some tests and if you have a test light and a digital multi meter. Get back to me and we do a couple of tests to try to figure out what it wrong.
Feb 28, 2009 at 8:18 PM
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JASON LOCK
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i am up for doing some testing. i have a test light and can come up with amultiditial tester
Mar 2, 2009 at 3:29 PM
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RACEFAN966
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Which fuse blows number 2 or 24? Get back to me Thanks.
Mar 2, 2009 at 7:02 PM
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JASON LOCK
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the number two fuse is the one that blows.
Mar 3, 2009 at 9:14 AM
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RACEFAN966
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Ok that fuse is the T-case fuse so we need to do some testing on the transfer case control module located on the steering column bracket. The wires for that fuse are all orange and it branches off to three orange wires. these are all battery in to the module. So you may have a bad module. However I need to know if any light come on when you push the 4x4 I know the fuse blows but do any lights come on or no lights? The tests are different for each. This could also be the transfer case shift motor on the back of the t-case. Get back to me with what you can and we will go to the next step.
Mar 3, 2009 at 10:17 AM
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JASON LOCK
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the light on the 4x4 switch does not work. no light.also the front drive shaft does not turn manually when truck is in park. does this matter?
Mar 4, 2009 at 8:47 AM
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RACEFAN966
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OK lets do a test to see what we need to do here. First I will need you to get to and unplug the 4x4 control module I have include a pic of where it is. Now I will need you to make a jumper wire so you connect each circuit to gound. So the pink and white wire ground it does this make the 4x4 low light light up? Now take the light green and black wire do the same and the pink wire and the tan and black. Did all the lights come one one at a time? If yes then the module is no good and need to be replaced. Let me know what you find.


https://images.2carpros.com/forum/automotive_pictures/249564_Graphic_47.jpg

Mar 4, 2009 at 10:58 AM
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JASON LOCK
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which side of the steering column is the 4x4 control module on? what i have located is on the left. it is 4inx5in x 2in thick. it has two plugs,one with 4 wires and one has about 30. i don't see a white ground. help
Mar 4, 2009 at 3:39 PM
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RACEFAN966
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It is on the left side of the column and the wire colors are like pink with white trace meaning the wire is pink and has a white stripe and the other wires are ment in the same manner. The module is on the steering column support bracket. Let know what you find.
Mar 5, 2009 at 10:25 AM
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JASON LOCK
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CAN YOY TELL ME WHAT THE 4X4 MODULE LOOKS LIKE?IS IT METAL OR PLASTIC AND HOW MANY WIRES DOES IT HAVE?
Mar 6, 2009 at 3:20 PM
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RACEFAN966
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First off no need to get frustrated I am trying to help and trying to do that with out the vehicle infront of me, much harder to do that way. Otherwise here is a pic of the t-case module I hope this will help..


https://images.2carpros.com/forum/automotive_pictures/249564_12577412_1.jpg

Mar 7, 2009 at 9:10 AM
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JASON LOCK
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i have located the tcase module.ihave found the trace colored wires.i cannot find a white ground wire on either of the two plugs. i don't mean to sound frustrated at you. i apreciate your help and patience. thanks.
Mar 7, 2009 at 2:49 PM
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RACEFAN966
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Ok it is a pink wire with a white stripe that is what I mean by pink and white wire. You need to make a wire to use as a jumper wire and you put one end of the wire into the plug (after the ends of the jumper wire has been stripped) and then touch the jumper wire to ground and do this with each wire that I have previously mentioned.
Mar 8, 2009 at 10:20 AM
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JASON LOCK
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i took a jumper wire and grounded it. ithen connected to the wires you mentioned before. no lights on the 4x4 switch lite up doing the testing of the wires.
Mar 9, 2009 at 11:47 AM
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RACEFAN966
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Ok now I need you to check for battery voltage at the pink wire at the shift selector switch with the module pluged in. If there is voltage then I need you to make sure the switch is pluged in and press all three buttons at the same time and check for voltage at the pink wire and then the dk green with white stripe and the tan wire with a black stripe. Let me know what you find. If this all tests fine then module is the problem. Let me know what you find.
Mar 9, 2009 at 4:44 PM
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JASON LOCK
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my shift switch has two buttons that are side by side. each button pivots up down. the left up is for 2x2. the left down is for auto 4x4. the right up is for 4x4 high. theleft down is for 4x4 low. it has two plugs. i have power to a brown wire only.
Mar 10, 2009 at 2:19 PM
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RACEFAN966
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Ok I need you to check 3 fuses for me. I need you to check fuse number 2 and 24 and 4. Also use your test light or multi meter and check to power to the orange wire at the module which should be hot all the time. Also check for power at the pink wire at the module which should be hot when the key is on. get back to me with what you find.
Mar 11, 2009 at 11:08 AM
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JASON LOCK
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the 4 and the 24 fuses are ok. the 2 was blown a new one was blown as soon as i inserted it. the pink wire has no power with the key is on. orange has no power at anytime. when the key is on there is power to a solid green wire and also to a solid brown wire. i noticed last night when my dash lights are on only the dash light on the left side button of 4x4 switch lights up the right button did not.
Mar 12, 2009 at 2:01 PM
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RACEFAN966
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Ok that fuse goes to the brake control on the t-case motor and then feeds power to the 4x4 module so that is why the 4x4 don't work. So with that you need a t-case motor it is on the back of the t-case. Sorry to put you through the tests but I don't like repacing parts and it don't fix the problem. Let me know how it goes.


https://images.2carpros.com/forum/automotive_pictures/249564_767746_2.jpg

Mar 13, 2009 at 10:47 AM
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JASON LOCK
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i installed the new motor on the t-case and my 4x4 now works. i didn;t mind doing all the tests as i don't like to just replace parts either. my indicator lights on my 4x4 button that tells which mode it is in doesn't work. do you know why? thanks!
Mar 18, 2009 at 1:15 PM
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RACEFAN966
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Great glad to hear that it works now there is a new problem. Ok lets check the pink wire at the switch, make sure there is power to it. Also check fuse number 9 and number 4. The pink wire should have 10 volts or more with the key on engine off. Then check the gray wire it should have power too. Let me know what you find here and we will go from there.
Mar 19, 2009 at 9:42 AM
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JASON LOCK
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i checked the 9 and 4 fuses and they are good. the pink and the gray wires do not have power. a brown wire has power when the key is on. if i hold the switch button in and play with the button the indicator light will come on but goes out as soon as i release the button.
Mar 24, 2009 at 11:29 AM
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JKBNOBLE
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Are you refering to the encoding motor for the push button 4x4? If so, can you tell me what it is like getting it out and replacing it? Thanks!
Mar 26, 2009 at 7:01 PM
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JASON LOCK
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when i say 4x4 button imean the switch on the dash which selects whether its in 2x2. 4x4 auto, 4x4 low, or 4x4 high. it can be replaced by taking lose the dash panel around the gauges and odometer.
Mar 28, 2009 at 12:08 PM
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EXCIDO
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Hi, thanks for the easy and detailed description and troubleshooting.

I have a similar problem.
1998 Tahoe (on small island of Guam so parts are hard to come by).

I use 4x4 allot getting boat out of the water. It was working fine until last week when it stopped working.

After reading your thread, I found that my #2 fuse was also blown. I replaced an 4x4 worked immediately - once. Now I blow a fuse every time I replace the fuse and the engage the 4x4!

Help?
Jan 2, 2019 at 10:44 AM
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STRAILER
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It sounds like the encoder is shorted out can you unplug it and then replace the fuse then try the 4x4 to see if the fuse blows. if not replace the encoder/actuator.
Jan 2, 2019 at 11:25 AM
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GOROUGHERS
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acts like hung in 4wd low when i accelerate rpms go way up wont go over 25mph dash controls for 4wd dont light dont seem to do anything this all started after putting in to 4wd check engine light not on
Jan 2, 2019 at 6:44 PM (Merged)
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JACOBANDNICKOLAS
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Hi:
It does sound like it is stuck in 4 low. Chances are the actuator is bad on the transfer case. Check to make sure there is power to the actuator. If there is, remove it and see if it responds when you switch the gears.

Let me know what you find.

Joe
Jan 2, 2019 at 6:44 PM (Merged)
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REDNECKCLAUDE
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1995 Chevy Tahoe V8 Four Wheel Drive Automatic

i just bought a 1995 tahoe.i have a problem with my 4x4 it not engaging. ihave checked all the fuses.also the light on the panle in the floor to show the 4x4 is engaged is not working.what should i check
Jan 2, 2019 at 6:44 PM (Merged)
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JACOBANDNICKOLAS
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Have you checked to see if the actuator on the transfer case is getting power?
Jan 2, 2019 at 6:44 PM (Merged)
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BK_FREEMAN1776
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This weekend we had a huge snow storm, and I had to use my 4x4 to get home and around. I was in 4h and it was working just fine and then all the sudden my windshield fogged up really bad and my 4x4 disengaged. Would you say it was my tranfer case vacuum switch? if so, where exactly is it located and is it easy to replace? What usually causes this switch go bad? Thank you
Jan 2, 2019 at 6:44 PM (Merged)
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JACOBANDNICKOLAS
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Check on the front axle for disconnected vacuum hoses.

Let me know what you find.
Joe
Jan 2, 2019 at 6:44 PM (Merged)
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CUPOFJOE84
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my 4wd is not working haved traced wires and all seems to be well. i have replaced the front accuator and the transfer case motor also got a differnt tccm and the switch on the dash. well icome to find out it does work in 4 low but 4 hi will not work. any help would be great.
Jan 2, 2019 at 6:44 PM (Merged)
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JACOBANDNICKOLAS
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Are you getting power to the actuator when you shift to 4 hi?
Jan 2, 2019 at 6:44 PM (Merged)
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CUPOFJOE84
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Front axle will get power but transfer case motor does not
Jan 2, 2019 at 6:44 PM (Merged)
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JACOBANDNICKOLAS
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Have you checked relays?
Jan 2, 2019 at 6:44 PM (Merged)
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CUPOFJOE84
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only relays are in the tccm, unless i am wrong
Jan 2, 2019 at 6:44 PM (Merged)
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JACOBANDNICKOLAS
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I believe there are relays for it under the hood. My mind is going lol It's been awhile since I saw one of these.
Jan 2, 2019 at 6:44 PM (Merged)
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PGLENN
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Selector switch light will blink briefly when selecting 4WD HI or LO, but reverts back to 2WD.. Will not engage 4WD.
Jan 2, 2019 at 6:44 PM (Merged)
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JACOBANDNICKOLAS
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Check to see if you are getting power to the actuator on the transfer case. If you are, chances are the actuator is bad.
Jan 2, 2019 at 6:44 PM (Merged)
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