I've got a '98 blazer and my service engine soon light recently came on. I tried hooking up an OBDII reader and it doesn't seem to work. I verified thy it works on my friends truck, but have no idea where to start. Any ideas?

 

Check the cigarette lighter fuse. It also powers the OBD port.

 

yeah, if the cig lighter doesnt work, then everything is dead at the port as well. i think that is a 20 or 25 amp fuse.

 

Thanks guys! Sure enough I checked the fuse and it was blown. Changed it out and the obdII booted right up. Now to figure out what's causing the P0420 code...