2000 blazer 4x4 trouble/help

Daughters 2000 blazer 4x4 did work last year. Got some snow here Sunday night (Boston) Ma. She tried to get up the driveway and seems 4wheel Hi will not engage. Well finally got up the driveway. Sounds like it wants to shift in 4hi I can hear some noise but it will not and the Light stays flashing on the dash. Tried the little fix that the owners manual said to do. Car in neutral-switch to 4hi then to park - then to drive. Still no 4 wheel. Called local shop and said it might me a actuator switch. Any suggestions/help? Where might the tccm switch might be located? Just got off the phone with tranny place and they said it might be a vacuum switch on the transfer case. Well was quoted of 90$ to have replaced.

Update to 4x4 problems.
Tranny shop was able to fix it was the encoder module. 350$ for part 135$ labor
tax and ?? total of 504$ all fixed. I was told the cover on the encoder was split and water got in side and corroded the lever and whatever. All fixed $504.oo oh well.

hi 2000 blazer here with 4x4 inop---can you be alittle more specific on your recent problem. i have no clicking and still am not sure where the tccm is on a 2000. a new encoder motor here is 550.00 at the dealer, i found one for 200.00. i just don't want to throw parts at it. if you can help at all please do...tomcat

Well i did not do the work had a tranny shop do the job. The encoder motor is on the transfer case and was all corroded from the cover cracked and water getting inside. the encoder was binding. so needed new one. I know on some of the post there are pictures where all the parts you mentioned are. If not just ask. I saw one post where you can disconnect the battery cable for 20min to see if you can reset any codes if not then have someone push the button while you can see under the hood and hear if it is engaging if not then might be electrical. Can be expensive to fix. I was told by the tranny place that the vacuum pot might be bad but the 2000 don't have that so it was the encoder motor that engages it to 4wd HI/LO. Good luck and please post back with the fix on your vehicle. People never post when they start a post and get the vehicle fixed and never tell people what was wrong.

Hey, Have a '02 blazer with no 4wd. I think it is the encoder also but haven't dove under the truck to see if I can see it. I almost had a coronary when the dealer told me the part is $650+. GMpartsdirect.com has it for around $325, still not exactly cheap. I found one on Ebay for around $125, probably a cheap chinese part but I am really tempted. What the F@#& was Chevy thinking when they designed this system, give me the shift lever back!

Does anybody know what the electrical pinout is for the encoder so I can test it?????

Sparky