My radio quit working. turns on and looks like it is but no sound. cleaned the wires on the harness going to the amp by the rear back door. but still nothing. some previous owner has done this before and it was all corroded really bad. car is a 2002 chev impala. also floor is always soaked on passenger side.. any ideas other than heater core ... fuses and speakers are all good

Here you go. Be careful this can disable the truck in some models due to the radio system be tied into the factory anti theft system..

2009 Chevrolet Tahoe Stereo Wiring Diagram
Car Radio Battery Constant 12v+ Wire: Red/White
Car Radio Accessory Switched 12v+ Wire: The radio harness does not provide a switched power source. The accessory turn-on is controlled by the lan serial network. Run a wire to the fuse box or ignition switch harness.
Car Radio Ground Wire: Black
Car Radio Illumination Wire: N/A
Car Stereo Dimmer Wire: The radio harness does not provide a dimmer wire. The dimmer wire is controlled by the lan serial network.
Car Stereo Antenna Trigger Wire: The radio harness does not provide a antenna trigger wire. The antenna trigger wire is controlled by the lan serial network.
Car Stereo Amp Trigger Wire: The radio harness does not provide a amp turn on wire. The amplifier turn on is controlled by the lan serial network.
Car Stereo Amplifier Location: N/A
Car Audio Front Speakers Size: N/A
Car Audio Front Speakers Location: N/A
Left Front Speaker Positive Wire (+): Tan
Left Front Speaker Negative Wire (-): Gray
Right Front Speaker Positive Wire (+): Light Green
Right Front Speaker Negative Wire (-): Dark Green
Car Audio Rear Speakers Size: N/A
Car Audio Rear Speakers Location: N/A
Left Rear Speaker Positive Wire (+): Brown
Left Rear Speaker Negative Wire (-): Yellow
Right Rear Speaker Positive Wire (+): Dark Blue
Right Rear Speaker Negative Wire (-): Light Blue

Below is an answer I found on line pasted it here - checked it out - found I had same problem. Additional notes from my repair...You must remove the scuff trim - pull back the carpet to get to the harness - inside the harness trace the two orange wires from the rear frontwards... the splice is approx. in line with the column between the front and rear doors...until you find the splice with a single orange wire - my splice was all green powder copper corrosion = no power. I pulled on the two rear wires and they immediately seperated form the single wire splice joint, came right apart - spliced -took about two minutes - radio works like new - good luck... I found the problem to be an orange power feed wire in the passenger side rear door scuff plate that totally corroded open. Evidently water came into the car interior through the fresh air vent below the front windshield and ran back though the wire harness tunnel. The splice area was just past the passenger rear door pillar where one of the orange wires was spliced into two smaller orange wires that provided power to the factory amplifier. Respliced the wires and now works great. Please pass this on as the most likely failure mode for this vehicles inop radio when the radio lights up but no sound. RICK

THIS IS A COPY OF A POST I SUBMITTED TO SOMEONE WHO HAD A SIMULAR QUESTION REGARDING AN ALPINE BRAND RADIO ISTTALLATION. THE PROCESS IS THE SAME NO MATTER WHAT BRAND THE AFTERMARKET RADIO IS.

Go to the store and buy a mounting kit and wiring harness adapter that are for your car. There are alot to choose from and most are universal and come with instructions. You can get these at wal-mart or best buy. The mounting kit is meant to fill in the empty space left by the new aftermarket radio (your alpine). The alpine will have a metal sleeve around it. take this off and put it in the mounting bracket so it is flush. The sleeve will have little triangle shaped tabs on it. Bend these out so the sleeve cant fall out of the bracket or someone will be able to pull out your radio. Remove your stock radio by pulling off the trim around the radio. This is held on by clips, so be careful. There will be a couple of screws holding in the radio. Remove these and pull the radio out. Behind the radio there will be 1 or 2 wiring harnesses plugged into the radio. Unplug these. Then attach the wiring harness adapters you bought. These plug into the stock harness and have wires at the other end that are labeled. Wire the alpine wiring harness into the harness adapters that you plugged into the stock harness. If you want to you can unplug the harness from the alpine and wire it to the harness adapter before plugging it into the stock harness. The wiring diagram should be on the radio. If not the colors are pretty common.
RED = SWITCHED PWR LEAD (IGNITION)
ORANGE = ILLUMINATION
BLACK = GND
YELLOW = BATTERY LEAD
GREY = FNT SPKR RIGHT(+)
GREY/BLACK STRIPE = FNT SPKR RIGHT(-)
WHITE = FNT SPKR LEFT (+)
WHITE/BLACK STRIPE = FNT SPKR LEFT (-)
VIOLET = REAR SPKR RIGHT (+)
VIOLET/BLACK STRIPE = REAR SPKR RIGHT (-)
GREEN = REAR SPKR LEFT (+)
GREEN/BLACK STRIPE = REAR SPKR LEFT (-)
BLUE = PWR ANTENNA LEAD
BLUE/WHITE STRIPE = REMOTE TURN ON LEAD(FOR SUBWOOFER AMPLIFIER)
There may be RCA jack inputs in the back and these are for the subwoofer amp.
There will be a large black cable in the back and this is the antenna wire. Plug in the antenna wire from the back of the stock radio here. Yu may or may not need an adapter for this depending on the size difference between the wire and the hole it plugs into.
**Please note: if your car has a "premium" sound system that comes stock with an amplifier you will need to attach the power antenna lead from the alpine to the remote turn on lead on the harness adapter. If not when you turn on the radio/cd it will not turn on the stock amplifier and the speakers will not work.
I found this out with my 99 dodge avenger which has an Infinity stock radio. You can pop the trunk and look up at the back dash and see the small amplifier.
Once the radio is wired and the mounting bracket is installed, connect the harness adapter as well as the antenna wire. The new wiring harness adapter makes the wiring a little longer so you may have to stuff them back a little bit. Connect the harness from the alpine back into the back of the radio and slide the head unit into the metal sleeve until you hear a click. Before sucuring the mounting bracket and putting the trim back on it is a good idae to try the radio out so if there is something wrong you dont have to disassemble it again. When you buy the harness and bracket it will say on the packaging "nissan 84-94" or "Honda 83-99" or something similar. Look on the back for a complete list of compatable models

please vote and thank you!

take the door panel off, disconnet the speeker harness connector using an anolog multimeter the one with the needle setting on A/C low voltage cause sound is transmitted thru A/C current putting the Pos. & neg. probes on the harness side turn on the radio and watch the needle move if it does'nt the radio went to hell or if it does then change out you speaker.

There could be a number of issues to look at. Does the motor work or is it a broken wireor is the fuse blown or bad ground to wiper motor. Check fuses first if O.K. go to the rear door panel & access the motor. Once there check the ground connection & make sure motor is well grounded. Turn motor switch on & using a probe tester check to see if power is getting to motor. If it is not, go to the wiring harness flex point between door & frame & pry back outer covering to reveal the wires. Check for a broken wire.If you have power & ground is good Take motor off & check motor on the bench using A 12 volt power scource. If it does not work replace motor. If this advice helps please fell free to recommend accordingly. Thanks!

Did it fail while you had vehicle, or like this when you bought it? Could be bad radio or wiring harness was chopped up when previous owners had an aftermarket radio installed. They probably just slapped the OEM radio back in when selling car. And didn't put all the OEM wiring back in.

check wiring on passengers side near the rear hatch speaker, the rear door speakers are run through them also. i had the same problem and it was a unplugged connector at that location

Hi, had total issues with this too! Your back speakers arent going because they are amped by the factory amp in the boot. You have to provide power to the amp so that it will turn the rear speakers on. This was a white and black striped wire in my car (Audi A3 1997) The rear speakers are blue /green and brown/red (left rear) , and the LH rear is brown/red and (forgotten colour) but the wire on the bottom left under those two brown/red wires on the 20pin harness. If you wire it all up like this then your rears should be going :)

If you still haven't fixed this, look at your wiring harness. The blue wire that comes off your factory harness is the external amp in the Infinity stereo. I found this out when I hooked my Pioneer head unit up. Coming off the aftermarket stereo should be a blue wire that says remote. Hook those up and you should be good to go.

You need to attach the blue wire on the stereo harness to the blue and white wire on the car adapter harness. they installed a small amplifier to power the rear door speakers and unless you connect those two wires then the speakers will not work.