I have a 1998 s 10 blazer 4x4 lt. 4.3 v6.
My 4x4 is working then nope does not want too/ I have replaced the following, All hoses to the system the NP1 encoder (junk yard) new actuator in the front and the transfer case switch actuator and the push buttons in the cab! All my 4x4 does is blinks thenn goes out (they both blink by the way)

 

Did you replace the transfer case control module (TCCM)?

I could see the possibility that the junk-yard component could be bad as it is nearly as old as your Blazer.

 

A lot of times the connections on tccm get dirty. People have cleaned them and it fixed it

 

Which transfer case do you have? You can determine this by the 4x4 switch panel: 3 button = NP233, 4 button autotrak = NP236.

The blinking then stopping means that the TCCM tried to engage 4x4 and failed. Do you hear the TCCM click when you press the button? It is in the passenger kick panel, and you normally are able to hear the relays click when you press the button. If they don't click then the first place I would start is what Newguy suggested, and clean the pins and contacts of the TCCM plug. They are prone to corrosion.

Also, read through this thread. And the DIY Tech article section has several articles about diagnosing issues with the 4x4 system.

 

Fortunately it is easy to get to the TCCM and work out if the problem is with its connector or the TCCM itself. On mine, I hoped it was the connections but they were clean and I had to replace the TCCM. Nice too as you don't have to get dirty to replace it.

 

thank you all for the help! I will try to clean the TCCM this weekend. My case is a NP1 3 button

 

When I replaced the encoder on my 3 button NP 1 with a re manufactured unit the instructions stated to clear the ATC codes by removing the 10 amp CTSY LP fuse for 5 minutes. Then program the TCCM to the new encoder by cycling the ignition switch off, run, off. 5 times before starting the truck. All the 4 wd lights flashed letting me know it took.

I'm not sure if that's required with a used encoder. But it could explain a system with good components not working correctly.

 

thank you I will try that good info!

 

Thank you Rusty nuts... Weird saying that but your advice worked great!

 

took a crap so I changed the last part I can do the TCCM works great now