I have a 2001 Blazer LT with 164k miles. My biggest problem happened after I had it for a week. I bought it at an auction for a great price. The car was bought off a dealers car lot but was repossessed. It was tuned up, new alternator, and other things replaced. The reason I believe was because the 4 wheel drive will not go out of 4wd lo. I found that the vacuum lines to the actuator and all the lines on the top of the engine where corroded to the point that the rubber was pliable. Even before I found that problem the lights on the dash for the 4 wheel drive selector only can on periodically. I spliced in new hose from below the engine and most of the top portion on top of the engine. Im still having the same issues so I was wondering what should I replace next. Should I replace the switches on the dash, TCCM, or anything else. Any suggestions would be appreciated.

 

I saw a youtube video on something like this... I think he said to replace every vacuum hose with a brand new one, making sure it is pulling as it should. He went on to say something about the actuator servo getting burned out and having to pull the transfer case apart to inspect the gears that were grinding(they needed replaced).

 

Hoses replaced. I changed the TCCM and switch. The switch was the problem, The fuse was blown as well so I put the original TCCM back and its all good now. The Auto 4x4 light is always on but it switches from 2 to 4 hi and lo with no problem. Thanks.