Hello I am driving a Chevy Silverado 1500 4x4 and I just took it in to get a water pump replaced. And all seemed ok until I drive it got on slick spot and put it 4 hi and it just kept flashing and didn’t click in so I decided to try all and non of them went in besides back to 2 wheel I was wondering if maybe a line got taken off and not put back on in the process or I got told maybe a actuator I found that odd cause it was working 100 % so I also noticed that my tow haul light keeps coming on and off Maybe has something to do the the Above issue ? Thanks for any suggestions given in advance.

 

I had a 99 that did the same thing, ended up being broken solder joints on the 4WD selector switch. I'd be willing to bet the tow/haul light issue is the fine wire going from the switch through the steering column has probably worn through from the many times the shift lever has been moved and the column tilted, so it is shorting and turning itself on and off.