Audio Systems: CD player installation causing lighting problems, haynes repair manual, chevrolet malibu

Question
I have a 1998 Chevrolet Malibu that came with a factory installed tape player.  About two years ago, my son and his friends replaced the tape player with a CD player.  The only problem at the time was that the dimmer control did not work on the interior lights. That was a problem I could live with.  A few months ago, they replaced that CD player with another one.  After that, other problems arose.  In addition, to the dimmer problem, during the daytime, the running lights work, however I get a warning lamp to take the car in for service.  This goes out at night when the interior lights come on.  I also noticed that during daylight hours, when the car is running and in "park", the parking lights stay on and when the car is turned off, the parking lights do not work when the parking light switch is turned on.  The switch works in the headlight position.

The original tape player came with a wire going to the engine control system to increase the volume level as the speed of the car increases.

Upon examining the wiring, I found 2 wires an orange and orange/white coming from the wiring harness.  They did not know what to do with them so they shorted them together.  Removing the short seems to have no effect on the lighting problem.
I have the wiring diagrams in the "Haynes Repair Manual", they make some sense, but seem to be incomplete.
I would appreciate any help you could give me on this problem.

Answer
John,
 

 we all start somewhere hehe.. i hope your son used a wire harness adapter its a plug that wires into the cd players harness then plugs into the factory plug.. if they didnt then its out of my hands.. but if they used a harness adapter and it sounds like they did that is good they made the first step to a good install.. i will give you some things to check out .. UNWIRE the 2 orange wires never splice 2 wires together unless they need to be ! .. also we will start with the simple stuff .. go to the fuse block .. check each and every fuse one at a time pull EVERY fuse not just the radio related ones .. replace if needed .. now i would un wire everything and if possible reinstall the stock tape player and check to see if everything works ? if you cant do this just redo the wiring from the cd player to the adapter quaddruple check the connections and use the haynes manual as a ref. and i will also give you a link to look at.. on most cars the illumination wire is not used normall an orange wire and good be the one/s you are talking about eitherway follow the colors and lables on both the adapter and the cd harness.. make sure all the splices are nice and secure and wrapped with black tape to keep everything from rubbing each other.. now if none of these help you out and returnin the system to stock doenst help if you can.. it might be a good idea to take it to a dealer to have looked at since it does involve some outside accessories such as DRL and the instrument cluster.. he may have shorted out a relay or inline fuse in the main harness.. hope this helps you out if you need anything else let me know

here is a link for some help with color codes
streetdreams.com/wires