I have an '04 Silverado 1500, V8 5.3L (not flex fuel). My check-engine light is on.

Took to Advance Auto to have the code read. Their scan tool could not link to my truck's computer. They said to check fuses. I did and found a blown Cig. lighter fuse. I also Googled the symptom and located many posts that point to the Cig. fuse as the cause.

However, code reader still doesn't work after I replaced the 20A cig. lighter fuse.

What's my next troubleshooting step?

Thanks in advance,

-M

 

If the fuse is good it should work..but there was another person earlier with this issue as well, so maybe this is something we havent heard of? most of the time its just the fuse

 

Check your fuse again. It could have blown again, indicating a short.

Also, does your cigarette lighter plugs work, or have electrical conductive debris in them?

 

Cig lighter is probably shorting out. OBD connection is powered by cig lighter.

 

Where is the fuse located? I have the same problem with my 2002 Silverado.

 

Open the drivers side door. There is a panel on the end of the dash that pops off to expose the fuses.

 

My fuse for the cig lighter socket was located under the hood fuse box and replacing it as needed was the problem for my truck. My 2002 model Silverado has three locations for fuses, one under the dash, one on the driver side end of dash and the one under the hood next to the battery.
My truck also has two other aux sockets next to the cig lighter that are on a separate fuse under the hood if I am not mistaken. I had blown my cig lighter fuse using a portable tire inflator.