I disconnected the overhead trip computer to install a radar detector. Traced out the wires and verified with the factory wiring diagram. Attached the wires to the + and - wires as needed. After plugging the connector in and turning on the key, I had no display. I went back re-verified that the key on + and - are good all the way through the connector and checked to see if the pins were bent on the overhead computer. All checked good. I disconnected the radar detector and still nothing.
My guess is that somehow I need to re-connect it to the FCM. I did try reseting the PCM(a long shot I know) but had no luck.
Can you guys help me?
2004 Dodge ram 1500 hemi QC.

 

Did you check the fuse for the overhead display. Probably the radar is using all the power and the overhead doesn't have enough

 

The overhead only gets a limited amperage, so you might have blown a fuse.

My suggestion is that you use + power from the Ignition Switched Aux Power socket in the dash and run a ground to the chassis.

You shouldn't ever hook up and share grounds on existing circuits in cars.

 

What?!?! That makes no sense. Yes, I did check the fuse. I also tried powering the trip computer without the radar detector connected, to include dis-connecting the radar detector wires all together so it was back to the way it came from the factory.

 

If you didn't replace the fuse with a new one, just go ahead and do that. sometime you can't tell by looking at them that they are burnt out.

I hope you were doing all of this wiring work with the battery disconnected by the way.

I also hope you checked the voltage and amperage of the circuit you connected your radar detector to before you just tapped it in.

If you over drew (too much current) it then you likely just blew a fuse, but if you shorted the overhead display b/c you left the battery connected when messing around in there you might have burnt out a circuit on the little board in there. (unlikely but possible)

Have you tried to test the lines for voltage with a multimeter?

 

The fuse tested good not just looked good. Yes all work was done with the battery disconnected. The only thing that overhead console saw was (with power disconnected) being un-plugged, then plugged back in.

 

Have you checked the wires to the overhead console for voltage?

If not that is your next step.

 

Try removing the overhead and take it apart to look at the LCD to see if it got burned out..... Mine was in the left hand corner of the screen I think the po of my truck tried to hook something up and messed up the overhead compass( at nite I can see lil lines on the screen), odometer LCD and heater wires.

 

Mine has been out for about 5 years now, never really thought about it...where/which is the fuse that powers it? I guess if I have it I might as well be able to use it...

 

I took mine's down the other day and tested the wiring for power and they passed maybe I'll go to the crap yard to see if they have one I can test than buy........ If you spliced into the overhead harness the detector might be taking more power if I remember there is only 10 to 12 I might be wrong but there is not a lot of power going there and if you read the fuse box top there is other things sharing the power from that fuse also