4wd mode light will not come on on 1997 Chevrolet S10

Recently purchase 1997 S10 Blazer and the 4wd mode light did not come on although it shifts fine into 4 wheel drive. I replaced the mode module and have the same problem. Is there a way to test the pins at the connector to see if it is the wiring without going to the dealer.

Asked by for the 1997 Chevrolet S10
Possible indicator switch on front differental or burned out bulb. ARE YOU SURE IT IS ACTUALLY GOING INTO 4x4? Ok 'how' do you know for sure? What are you calling the mode module, the selector switch? 'IF' it's going into 4x4 and you just want the light to come on then try to repair the light circuit, nothing else cause the rest is working! With 4x4 active drive it slowly on pavement (parking lot) and turn the steering wheel hard left or right, does it act like it's in 4x4? If it is you will know by the way it feels, like it's binding up or buckin, or try to spin tires in the front yard. Oh, I own a Blazer too, so if you find it is not going into 4x4 i got more info. if needed.