hey guys I got a 98 4x4 blazer and the 4x4 has always worked. went to use it one day and it doesn't.

When you press the button on the dash to 4hi or 4lo, you hear the TCCM click. but nothing happens.

you can keep pressing it but just a "click" every time.

any ideas on what this could be?

I tries to put a new switch in the dash because my old ones clips where broke off anyway, but it still does the same.

any ideas on where to start checking? thanks guys.

 

Its a possibility it can be your transfer case in that general area

 

I believe this is the same symptom I had on my '01 a few months ago. The problem was a dry rotted rubber vacuum line going to a solenoid switch that is mounted to the firewall under the hood. The vac line had fallen off the solenoid and just crumbled in my hands when I tried to reconnect it.

I just cut away the rotted rubber vac line, installed an in-line vacuum adapter into the remaining good line and new vac hose on the other end of the adapter to the solenoid. Problem fixed !

Bill

 

Check the FWD system for codes, ground pin 13 (or connect pin 4 to pin 13) of the ALDL connector under the dash on the driver's side. Turn the ign key to "on" and observe the 4x4 button LEDs. they should flash a code (1 thru 4). If you need the meaning of the codes I can post them. (they're probably on the net somewhere). Good luch...



Also check the encoder/motor on the left side of the transfer case next to the front driveshaft. To remove it you'll probably need to pull the front driveshaft, but measure the voltage going to the 4wd shift motor (two person operation, one to push buttons and one to measure voltage) see plug pinout at WWW.RLFARMS.com/blazer/ if you have the 4 button 4x4 look at RLFARMS.COM/blazer/4button/ if you need the button pinout.