4wd troubles...cant drive

[pinhead989]

ok i posted about this problem b4 but now i finally got some information on this...one day the 4hi wouldnt work ( hit the button and nothing happens) throw it in neutral go bout 2mph hit 4lo it would clunk in the front end and go back to 2hi do this about 4 times and it went into 4lo. second snow storm i needed 4wd hit 4 lo same thing 4 times later it goes in. now no lights came on but in 4lo, hit 2hi...nothin. drove her home and when i went to shut it off the box in the passenger side thing constantly clicked even when the vehicle was off so got it towed to a tranny shop they did some tests and said nothing is showing up on the dignostic thing,vac lines and parts look to be good no leaks.they suggested it could be a computer problem. so i went home came on here and look someones advice and disconnected the battery overnight, next morning hooked the bastard up and now all 3 of the 4wd lights flash but still no clickin or anything. so my question is is there anyway to manual or something put it in 2wd until i get money to get her fixed they wanted 700 bucks for a new computer IF it was that.



so this is so long im just dumbfounded with all this 4wd i never had to deal with it until this truck

99 blazer 98000mi automatic electronic 4wd 3 button

brian

[s10468]

Brian, disconnect the vacuum hose that supplies vacuum to the actuator under the battery and your front axle will disengage allowing you to drive normally until you can properly fix the system. If you search the archives on this forum you will find many people that have replaced the TCCM (computer) without success. The mechanical problems with this system are easily fixed, unfortunately the electrical side of the system is far more difficult to diagnose and correct. Some of the possibilities: broken wires, bad sensor or switch, corrosion on connectors, bad encoder/motor. Buy aftermarket components not dealer parts. $$$

[pinhead989]

do i have to keep it off or disconnect and reconnect?

[duke350]

pull it off, plug it up and keep it off. The front axle will only engage when there is vacuum to the actuator.