99 chev blazer, service 4wd light is on. Simple things to check before the mechanic

Check the vacuum switch under the hood in the center of the firewall...follow vac diag

There is no one answer for a problem like this.

easy you remove anything thats in the way ,mechanics nightmare i know but ?? try working on a renault or a citreon

Your 4WD control module has detected a problem in one of the circuits that are controlled by it. You will have to scan your computer system to find out what circuits are failing and diagnose the problem according to the fault codes retrieved from the computer.

one of my vehicles is actually a 2000 blazer and i had that same problem believe it or not. you should check all the connections to the brain of the 4wd. take off the passenger side right side kick panel. the kick pannel is that piece on the side right there next to the door. take that off and you will see a grey box. pull the wires out and look at the ends. i cleaned mine out with a q tip because there was crud in one of them which screws things up. if that doesnt fix it you may need a new one. they can be really expensive from a dealer so i went to a wrecking yard and pulled one out of another blazer and it only cost $20. it works fine now :) i hope that helps.

Ok, first, you should clear the fault. Sometimes the system will get a bug, and there's not really a problem. You can do this by disconnecting the battery for 10-20 minutes. This will clear any faults. Next, see if the light comes back. If it does, then you can take it to get the codes scanned at a parts store(many do it for free.) Once you get the code and description, you have to troubleshoot the specific system that the code covers. The check engine lights are usually triggered by sensors going bad. On occasion, you will get an actual mechanical failure that will cause one.

did you try completely stopping the vehicle, puttin the shifter in neutral, and putting it in and taking it out of 4-wheel drive?

Shifty_Tazz

check control box on pass. side,under kick panel,check elect.connector for corrosion,usual suspect! on 96 and later blazers with elect,shift,hope it helped!

Hi...
I own a 98 blazer. There's a module that has failed in the 4WD part of the truck . I had to have mine replaced at about 70,000 miles

I have a 1999 chevy blazer that stuck in 4 wheel drive. How do you get it out.