I tried to have Autozone find the code behind my check engine light, but apparently my diagnostic port is broken. check at O'really's and Advanced as well, and their machines also couldn't detect that they were plugged in. I've checked all my fuses, including cigarette lighter fuse and nothing is blown. How would I go about trouble shooting the issue? My truck is a 1999 Dodge Ram 1500 5.2L 4X4 Sport edition. Thanks

 

There is one fuse that I can't fully check, IOD fuse (10A) , because it has this wierd plastic guard on it that looks like it should make it easier to pull out, but instead makes it impossible. Does anyone know what this thing is and how I can remove it without breaking it? Several other fuses have them in the same fuse box. It looks like little wings on the fuse and acts like a cage around it when you try to pull it out.

 

Radio will not work with dead iOD fuse, if you really want to check them, grab the wings and apply pressure, it will allow you to raise them up, then you should be able to check continuity across the fuse with a multimeter.
The port should have power at pin 16 and ground at 4 and 5.
You should be able to read flash codes or your cluster display by doing a key dance (cycle key from off to on 3 times and count light flashes or read display if equipped)

 

I don't think the 98's will do the key dance trick......

 

If you've ever had moisture in the cab, the terminals might be a little corroded.
Pushing the plug in and out of the connector a hand full of times might clean up the contacts.
Follow this with the lightest of light smear of contact grease (apply with a cotton bud).