Where do I plug in the code checker????

[Strieg]

I've looked under the driver side and passenger side?? Idk where this plugs in at.

 

[Strieg]

Ok I found it but the device doesn't seem to be working. I had the key off. And the Device plugged in, but then turned the key on and nothing happened. No lights no nothing

 

[Earl43P]

http://www.therangerstation.com/tech_library/OBD_I.html

 

[Strieg]

Ok all done. The problem with my checker was failure to insert a battery. Lol
So I pulled a knock sensor code