Hey,
Just last Saturday I purchased a 2004' Pontiac Sunfire, and so far love it. Only problem with it was the stereo, as it would not read CD'* properly. Weather they were burnt or not, it would take them in, then spit them out and say ERR.
Today I bought and wired a JVC single DIN stereo for my car. I matched the wires properly, and I ran a wire and fuse adapter plug from the power on the Stereo to the inside fuse box. I first had it plugged in to the windshield wipers, as the stereo would then turn off when the car turns off. The stereo worked fine, and would play music, etc, but my HUD was all messed up. For starters, the odometer will read "error" instead of the kilometers, the fuel gauge stays at E, my speedometer stays at zero. Basically, the HUD isn't getting the power it needs. If the stereo is turned off, then the HUD reverts to normal, and everything'* fine, but as long as it'* on, the HUD is messed up. I've tried plugging the fuse connector in to multiple spots, like the stereo, windshield wipers, cigarette lighter, and audio amplifier fuses. Does anyone know what the problem is? I'm using the right amperage fuses, and all the other wires are spliced properly. Is it because the aftermarket stereo is not connected to the car'* computer, or is it because the fuses aren't connected properly?
Will I have to get a wiring harness for the new stereo to work, or is there a way I can directly wire the ignition cable from the stereo to the fuse?
Any help would be awesome.
Thanks!

If you can, put the OEM deck back in and see if your still having the same issues.

I'm suspecting the data bus has been compromised with the new deck install.

Check your ground. Try grounding to the chassis rather than a wire in the harness.

Also, going on Mike'* theory that the data bus could be compromised, could you have wired the data line into an output on the radio by accident? Perhaps try disconnecting everything but the power, ground, remote and see if the radio being on still disrupts the dash. Then start adding wires in till you see a problem.

Ok. I've re-wired the factory deck back in, and it isn't giving me any trouble. Everything that was working before, is working now. The only problem is the lens on this stereo won't read CD'*. That was the hole point of me getting an aftermarket stereo, so I could listen to CD'*. Do you know if there are step by step instructions for installing an aftermarket stereo in to this type of car? I have a buddy who is an electrician and did this to his 2001 Sunfire, but his obviously required different wiring. I would much prefer to do this my self, rather than take it in to get it done, as the installation fees can get quite costly.

I actually don't have the coaxial plug for the radio in the stereo right now. I need an adapter cause the factory plug is too small for the aftermarket stereo.
When wiring, I had the color codes for the car and the codes for the stereo with me, and matched everything. I did have my electrician friend with me, (he actually most of the work). We didn't notice the HUD problems when we tested it, so he left before I noticed it. I think I'll try bringing it in to a GM dealer tomorrow, and seeing what they say about the wiring, and about the data bus. I'd bring it in tonight, but all the service centers closed 2 hours ago.

No sir, I only wanted you to reinstall the OEM deck to make sure the systems work with it back in.

Right now, the only recommendation I can offer would be to purchase a special harness for your make and model.

Electrical 101, the databus in your car is a daisy chain of sub systems. PCM, BCM, Trans Controller, ABS, ALARM, Door locks, windows, lighting etc etc etc. Everything is designed to work with each other. If one system is removed, it compromises everything else.

the aftermarket radio has no bearing on the car if you leave the data bus wire open. so if the radio is working other wise but wont play cd'* there is something wrong with the radio.

Unless he miswired something. God forbid he send 12v along the data bus.

Sorry, I might not have been clear enough before. The factory radio has a lens problem and won't read CD'*, the aftermarket stereo plays them just fine, and when I had it wired in, it worked perfectly, except it was causing other problems to the car, ie the HUD errors. I have removed both stereos, and a family friend who is a professional electrician and heavy duty mechanic (not just an electrician'* apprentice) is helping me with the wiring. I have all the things I need to wire it properly now (wiring harness, tools, parts, experienced professional), but thank you guys so much for your suggestions and help. I probably would have messed something up if I just went out and tried to see what I could do.