i have a 1999 4 door chevy blazer last night when i was driving home for about 2 min. sitting at a stop light the service 4wd light came on. I got home and hooked it up to a scanner and nothing was reading. Also checked stored codes and nothing.

i have a 1999 4 door chevy blazer last night when i was driving home for about 2 min. sitting at a stop light the service 4wd light came on. I got home and hooked it up to a scanner and nothing was reading. Also checked stored codes and nothing.

You need a transmission /transfer case /body capable scanner to get body/transfer case codes.
MT

can you get this done at autozone or o reillys or do i have to go to tranny shop?

Most AZ or other parts places can only read OBD 2 codes.
I would check around fo a good repair shop.
Good luck
MT