Im sorry if this is going to be long and hard to understand but ill try and make it as clear as possible. I have a 99 blazer 4 door. When you hit 4 lo it engages and works the way 4lo should. When you hit 2hi to get it out it goes into 4hi for a while then while driving it usually clucks and goes into 2hi. When you hit the 4hi button while in 2hi nothing happens no lights blink. When you hit the 4lo button sometimes both 4hi and lo buttons light up and sometimes none do. When i first bought this truck it needed a new transfercase motor, so i replaced that not now its doing this. Many poeple have told me that i istalled it wrong and now its getting a fault.

 

Hum, was reading your post. I bought my used blazer this summer and there was no manual. I've only been using the 4 wheel drivefor a month or so but the 2 wh hi button dosn't light or seem to switch the drive for me. I have to stop the blazer and put it in park to take it out of 4 wheel.
Now my problem- Monday at 5 a.m. I used the 4 wh dr to get out of my drive, half way to the ferry I pulled over, put it in park, put it in 2 wheel and drove to the ferry terminal. Parked and left the keys for my friends to pick up the blazer. A few hours later they put the key in the ignition and it is locked. They can not turn the key and the wheel is locked too. They have been trying for two days to move it out of the lot before the police do. Any suggestions?

 

try wiggeling the key while trying moving the wheel

 

You have already posted about this issue in another member's thread that actually dealt with a locked ignition cylinder. Please do not double post (especially in unrelated threads) since it is against Forum rules.

 

From the sounds of it, you have the 3-button switch in the dash. If this is the case, check for codes stored by the TCCM. This is documented in the Non-Automatic OBD2 Transfer Case Diagnosis thread in the Tech Article (DIY) section. Let us know what the codes are that get returned.

Some other things you can check are the electrical connections at the encoder motor (on the transfer case), the TCCM (behind the passenger side kick panel), and at the dash switch for corrosion.

 

Just wanted to add something to my orginal post...ive tried removing fuses and keying the truck and does nothing, but if I unook the battery for a few seconds an hook it back up and i hit 4hi it goes in no problem... until it kicks out by itsself. Not sure if this changes what could be going on or not. Its been very cold here the last few days and ive not been able to do the tccm test but i should be able to get it done tomorrow and ill post my results.