Hello, this is my first post.
I have a 2004 rx8. I never messed with the speakers, only tried to put an aftermarket double din head unit. After it was all hooked up, the head unit was defective. I returned it, and in the mean time I had to order a new wiring harness for the stock radio (metra for protege 03-09 {compatible with 04-08 rx8}) and after I triple checked all the wires, and made sure the two center inserts were hooked up, the display works, my HVAC works, and the radio seems to play FM/AM and CD just fine, however there is no sound? As well as my steering controls stopped working, and the display on the radio seems dimmed, compared to the rest of the vehicles display I.e. lock button, window buttons etc. What's going on!? I've checked all fuses, and everything. I should mention there were 4 wires that didn't need to be hooked up, and I'm having a feeling they may be my steering controls . again I plugged all harnesses back and checked all wires. Again I've never messed with the speakers nor were they close to being blown.

 

Sounds like you shorted something but it could be many things, it's hard to say without actually looking at it. I assume you disconnected the battery while doing this work?

 

Yes of course, however after I hooked everything up, I got confused from the 12v ignition wire I believe (green/orange) and I saw no such color, only green/red green/yellow, so I tried both, and I got a quick spark when I found the proper one. I checked my fuses right after and they were all fine. Could this be the cause? It was literally a split quarter second the spark came up before I separated them . turns on it was the green/yellow.

 

A short is a short and it sounds like you shorted it so the only way to know for sure is to break out an electrical diagram and a meter and start testing things.

 

@9krpm
What exactly do I need to test?

 

Honestly if you have to ask then you should probably take it to someone. But pretty much any harness related to the radio/center stack.