afwd switches automatically

[koeneke2000]

I have a 2005 Trailblazer LS. About once every two weeks while driving down the interstate, usually at about 70mph, I feel a clunk and the afwd light is blinking. It usually lasts a minute or so and then goes back to 2wd. Could this be a faulty switch?

[MTPockets]

Could be the dash switch or the encoder motor in the transfer case. Check the connections at the transfer case and 'exersize' your 4x4 by going thru the ranges every once in awhile. Yours is a tough one because if you take it in, the techs probably wont find a problem.

Joel