I have a 99 Dakota sport 3.9 2wd. Theres no check engine light but still the reader won't read anything at all.. no power n also my radio is all messed up turns on but won't actually turn on. Has power but won't actually open (it's a flip up GPS) I'm not sure what's going on with it but also I turn the car on and all the lights show as normal but when I open door no light for it when I take seatbelts off no light comes up.. what could be the issue??

Already checked all fuses and relays theres no power to it cig lighter works and everything too

Sounds like a short to it .Or contact issue.
Get diagram on wiring an test it from fuse to connector .
maybe something on same fuse has issue ..

I'll check into that. I was thinking maybe a ground is no good somewhere

That too.
test Ground

I've been checking everything I don't see anything that would cause this problem. When I first got the truck the computer had issues so I got new plugs and sealed it but it may be that. I'm not sure I'm done for today tho will look more tomorrow. Just hope I can figure it out sooner rather than later

So you tested wiring that goes to it from fuse box ,and anything between the end of obd and fuse box?

A wiring diagram can always be good to have.!
It shows the exact ones to test from ECM too.