the electric servo and or the switch is bad.could be one or the other. A common problem if not used in some time.
Turn signal flasher relay is defective. Is located under the dash, driver's side.
The Owners Manual sez to be in Neutral when changing from one mode to the other.
It could be the shift motor on the T Case. Or it could be the automatic shift button switch on the dash.
If your year/model truck has the push buttons on the dash to engage the 4x4 check to see if the 4x4 button is stuck in. Bump the dash panel with your hand or try to gently pry it out if it is stuck.
4x6 in the front dash
On a 1999 GEO Tracker, a bad fuse can cause the headlights and dash lights to blink. A bad voltage regulator or alternator can also cause lights to blink and flicker.
When your 4X4 dash lights blink that is indicating a malfunction - could be just a sensor
If you have no dash lights at all on your 1989 S10 Blazer, a blown bulb can be the problem. You should also check the fuse.
Check engine codes are generally read with an OBDII reader that connects to a data port under the dash. As far as I know, no cars allow you to check them by pressing buttons on the dash.
Worn brake pads can cause the brake light to blink on the dash in a 1993 GMC Sierra 1500. This can also be caused by a faulty light.
Is the bulb burnt out? Change the bulb and it will blink at the dash and light. If it still doesn't work, check the turn signal relay.
Check your buttons. You can pull out the button module from the dash. Then separate the back from the front. Use a q tip with alcohol to clean the points of contact between the buttons and the electronic board. This is an easy process and it worked for me. The connections tend to get oxidized.