Chevy Blazer 4 x 4 and Engine Light Problems

I have multible questions for my 1996 Chevy Blazer LT. When I bought it 2 years ago the 4 x 4 worked fine, but last winter... no 4x4. I checked the cable leading to the ''actuator / transfer selector?'' and removed, cleaned it. It was loose before I did this and afterwords, 4x4 was back! Hadn't used it since last winter till about a month ago, got stuck on a job site and was pulled out because it wasn't working, again! Any ideas???????? Now my second question. I had an engine light check 2 weeks ago and got it cleared. It was a p1870 manufacurer controlled transmission, something about slippage. Would this cause my 4 x 4 not to work. Third, I am getting an airbag light now that comes on while driving and randomly goes off. PLEASE HELP ME. I swear I hate newer cars................