I'm new to this site and I am having problems with my 98' S10 blazer. I road over a log like the size of a telephone pole and was switching it in and out of 4WD all the sudden both lights started flashing and now I can't put the truck into 4WD HI or 4WD Lo but if I put it in Nuetral and push 4WD LO both lights will flash and 4wheel low will engage. No 4WD HI? Any info would be appreciated.....

Get on your back, get under the truck and look for any damage underneath. Chances are you have damaged the axle switch on the front axle or maybe broke or pulled something off of the transfer case. Look for rub marks or bent places under the truck, it might help point you in the right direction. Good luck.