4x4 not engaging

[project96]

Hey everyone, my 4x4 is not engaging in my 96 tahoe 5.7. It's got the electronic switch on the dash. When I hit the 4hi setting the light just flashes forever and will never seem to engage into 4x4. If I hit the 4lo setting it seems like it engages, the 4hi light stays constant and 4lo light flashes. Any ideas?

 

[SunlitComet]

Check some things first.
The blinking light indicate incomplete axle engagement.

Get yourself a multi meter that can measure 10 amps.

Remove fuse #24 ensure it is not blown and configure the meter on the hi-amp setting.

Connect one lead to each terminal on the fuse block(DO NOT LET THEM CROSS).

Select 4hi and watch the meter if you see a brief amperage rise then your t-case 4wd shift indicator switch($40) is worn or the cam in the case that drives it has something wrong.

If you see a continous draw of several amps remove the front axle actuator and engage the 4hi again.

If the actuator extends then the likely culprit is the other "axle engaged" switch($30) also located near the actuator.

If the actuator does not engage and the light blue wire on the actuator shows 12+ volts when 4hi is selected then replace the actuator($80).

If you need more help just ask I have a lot of tech info on this system.

Good luck.

 

[project96]

Hey thanks again man I will do the following tests as soon as I can. Unfortunately I have to work the whole weekend (12 hours shifts) and I will have time on Monday to do some tests. I will let you know how it goes...cheers!

 

[project96]

Update: so I set the multimeter to 10 amps and hit the 4hi button. There was no amperage at all it just stayed at 0. Is this a good thing? However i did notice the transfer case making noise everytime i hit the switch from 2hi to 4hi.

 

[SunlitComet]

If you are sure that the fuse in your meter is also not blown, put a known good fuse back in the vehicle fuseblock. Go for that light blue wire for + and the black wire for -on the acuatator connector. Meter set for voltage. Have some one hit the 4hi button for you if you do not see your 12 volties go for the switch on the transfer case. I should have a link below to picture where that switch is (Label #2). You can figure out the other three I am sure. It sounds like your t-case shift motor is fine though. Just probably that switch or the cam in the case that hits it.

Should be available locally to you.

http://www.sunlitcomet.com/images/automotive/62392474.gif

http://www.sunlitcomet.com/images/automotive/62392160.gif

http://www.sunlitcomet.com/images/automotive/62392161.gif

http://www.sunlitcomet.com/images/automotive/62392162.gif

 

[bsamoul]

Check some things first.
The blinking light indicate incomplete axle engagement.

Get yourself a multi meter that can measure 10 amps.

Remove fuse #24 ensure it is not blown and configure the meter on the hi-amp setting.

Connect one lead to each terminal on the fuse block(DO NOT LET THEM CROSS).

Select 4hi and watch the meter if you see a brief amperage rise then your t-case 4wd shift indicator switch($40) is worn or the cam in the case that drives it has something wrong.

If you see a continous draw of several amps remove the front axle actuator and engage the 4hi again.

If the actuator extends then the likely culprit is the other "axle engaged" switch($30) also located near the actuator.

If the actuator does not engage and the light blue wire on the actuator shows 12+ volts when 4hi is selected then replace the actuator($80).

If you need more help just ask I have a lot of tech info on this system.

Good luck.

My actuator engages for sure but I still have nothing. I feel the problem in my truck is in the front diff?