Hmm.
First try this
http://www.installdr.com/Harnesses/DCP-Wiring.pdf
If the color code matches what you have in the car then great.Otherwise it is hard to say. There may be an amp or not.
Here is a thing you can try:
First strip every wire about 3/8 inch make sure they DO NOT TOUCH!
Step 1: Find the ground: With an ohmeter find out wich is the ground wire.
Step 2:With the ignition off, find the 12volt wire with power using your voltmeter and the previously found ground wire. This is the "battery" wire that always has power. This is what will connect to your Yellow deck wire.
If you cannot find any wire with 12 volts on it, a fuse is probably blown. Check that next.
step 3: turn on ignition to accessories and with the voltmeter find the wire that now also has power. This will connect to the RED deck harness wire.
Step 4. now find the speaker wires. There are 2 ways: either remove all the speakers and find out what is what by following the color code, . Or use an ohm meter to find what remaining wires are connected to speakers. If it is a system without an amp, you should read about 4 ohms. If it has an amp, it will read much higher. 100 ohms or thousands of ohms.
Now that you found out what wires are connected to the speakers, you must check polarity of the speakers. 99.99% of speakers are wired so that the cone moves out when the Plus side of a 9 volt battery is connected to the Positive of the speaker. Once you find it, then mark it with a red marker or something. Then follow the collor code of the speaker wire back to the dash and mark front/rear/left/right/ pos/neg. There will be a few wires left over, One may be a power antenna wire the other may be a light dimmer. Again, with a volt meter check the remaining wires with and without interior liights on to find what is the dimmer. The left over one should be power antenna.
This is a general guide. but car companies always tend to throw curve balls. If you do not own a volt/ohmeter and know what ohms law is, then I suggest you bring your car to a good installer to re attache a harness. If