Originally Posted by
6.9 Diesel
the light comes on when the key is turned on, but quickly goes out so i kniow its working,......
How can they fail if for not working when it works? Obviously, it's a problem for their computer communicating with the truck's computer. As already pointed out, the power to the computer port runs off the same fuse as your cigar lighter. If your cigar lighter doesn't work due to no circuit power, you also cannot pass an OBD-based inspection on one of these trucks. Fuse # 3 in the under-dash box.
had a 93 f150 i was working on. they had pulled the bulb out for whatever reason. would not start until i put it back in.
Ford never has done such a thing. Coincidence.
Steve