I recently purchased a 1998 4 door 4x4 blazer and it runs great. Although when I put it in 4 wheel drive the light flashes and then switches over to 4x4 high but you can't feel it grip the road and I've tested it by going into a mud hole and I had it in 4x4 high and only the back tires spun the front tires were just normal. I also tried the same thing in 4x4 low. If you have any possible solutions please reply thanks!

 

I have the same problem. Looking for help too. Maybe the vacuum diaphragm under the battery? Maybe the guru's will chime in with their wisdom.