I have a 1999 Chevy Blazer with a 4x4 problem. Transfer case is a 233 automatic.
Push button dash mounted switch (2hi,4hi,4lo)
With the blazer in park it does not go into 4hi. If I put it into netural and push 4hi button, the 4hi and 4lo buttons blink a couple of times and goes back 2hi being light. If also in netural and I push 4lo button it engages into 4lo. You can here the transfer case motor switching. Then 4lo is engaged. Also when in 4lo the dash switch does not indacate im in 4lo. As soon as you step on the gas
[/align]you can tell its in 4lo. Any help would be great before I start putting $$$ into this again to fix it. Thanks.

 

Start by checking the TCCM for stored codes > CLICK HERE.

If not codes are present, check all electrical connections for corrosion. That includes at the switch, the TCCM (which is behind the passenger kick panel) and at the encoder motor on the transfer case.

These problems are most commonly caused by a fault in the encoder which is what tells the TCCM the position of the transfer case sector shaft, but it pays to check the simple and cheap things first.

What happens if you disconnect the battery for say 15 minutes and then test the 4wd system? Do not do this until after you have tried to test for codes.

For further information on the NV233 transfer case, CLICK HERE.

 

Ok checked all my connections, and everything looks good. No corrosion, rust, and none are bent. Grounded pin 13 on the DTC and the shift lights, all three (2hi,4hi,4lo) blink 2 times. Then theres a pause, then blink 2 times. Over and over till I turn the key off. It say that DTC 2is ENCODER FAULT. Im going to dissconnect the battery for abit to see if that clears the code and fixes the fault. Ordoes theencoder motor need replaced? Thanks

 

Ok I disconnected the battery for at least an half hour while I did some other work on it. I tested for any saved codes when I reconnected the battery and none were saved. All cleared. Took it out into the snow and hit the 4hi button and what do you know, it worked. I messed around with it for a bit going into 4hi,4lo,2hi,4hi. After abit it stoped working. It went back to doing the same as I described above. After that I tested for codes and yet again all three(2hi,4hi,4lo) buttons blinked twice, paused, blinked twice etc.... So im taking that the ENCODER MOTOR is bad. Any thoughts before I replace it? Thanks for the help

 

If all of your connections are good and clean, even the ones down on the encoder motor, then yes, I would say that the encoder motor is at fault.

 

Thanks for all the help. Id be lost if it wernt for this form. It kicks A$$. Ill be replacing the encoder motor some day soon. The next project is balljoints upper an lower plus half shafts. Hope that all goes well. Any ideas on good aftermarket half shafts? Got moog balljoints. Thanks for all the help.

 

Glad to help!