Here is the stereo radio wiring information for your 1988 BMW 325ix E30 with the standard or amplified systems. It will be useful when installing an aftermarket radio, sound stereo system, or other automotive accessories. Make sure to grab the appropriate tools to test all the wires in your 325i E30. Please check it over and use it as a GUIDE to help you locate the appropriate wires. This schematic is provided free of charge and may not be 100% accurate. Failure to properly test all the wires may lead to vehicle or bodily damage. All information is provided as-is and accuracy is not guaranteed.
If you find any conflicting info please leave a comment with what you found in your 1988 BMW 325ix E30. If you don’t see the audio radio wiring diagram you need comment and we will try to add it ASAP. Thanks for looking!
(MAKE SURE TO SCROLL TO THE BOTTOM TO SEE IF ANY OTHER READERS POSTED ANY OTHER TIPS AND TRICKS!)
1988 BMW 325ix E30 Audio Wiring Radio Diagram Schematic Colors
Car Radio Constant 12v+ Wire: Red/Green – @ Stereo Harness
Car Stereo Ground Wire: Brown or Brown/Black – @ Stereo Harness
Car Radio Ignition Switched Wire: Purple/White or Purple/Gray – @ Stereo Harness
Car Stereo VSS Speed Wire: N/A
Car Stereo Reverse Backup Wire + : N/A
Car Stereo Dimmer Wire: N/A
Car Radio Illumination Wire: Gray/Red (+) @ Stereo Harness
Car Stereo Power Antenna: White (+) @ Radio Harness
Car Radio Amp Turn On Wire: White (+) @ Radio Harness – Same wire as above.
WITHOUT OEM AMP: SPEAKER WIRE COLORS AT THE SPEAKERS OR AT THE FADER SWITCH ABOVE THE RADIO – MUST CUT AND CONNECT
Left Front Speaker Wire (+) Positive: Yellow/Red
Left Front Speaker Wire (-) Negative: Yellow/Brown
Right Front Speaker Wire (+) Positive: Blue/Red
Right Front Speaker Wire (-) Negative: Blue/Brown
Left Rear Speaker Wire (+) Positive: Yellow/Black
Left Rear Speaker Wire (-) Negative: Yellow/Brown
Right Rear Speaker Wire (+) Positive: Blue/Black
Right Rear Speaker Wire (-) Negative: Blue/Brown
Center Channel Speaker Wire Positive / Negative: N/A
Subwoofer Speaker Wire Positive / Negative: N/A
WITH OEM AMP: SPEAKER WIRE COLORS AT THE SPEAKERS OR AT THE AMP DRIVER SIDE TRUNK AREA
Left Front Speaker Wire (+) Positive: Gray/Red
Left Front Speaker Wire (-) Negative: Gray/Purple
Right Front Speaker Wire (+) Positive: Gray/White
Right Front Speaker Wire (-) Negative: Gray/Brown
Left Rear Speaker Wire (+) Positive: Black/Red
Left Rear Speaker Wire (-) Negative: Black/Purple
Right Rear Speaker Wire (+) Positive: Gray/Red
Right Rear Speaker Wire (-) Negative: Gray/Purple
Center Channel Speaker Wire Positive / Negative: N/A
Subwoofer Speaker Wire Positive / Negative: N/A
Radio Size: Single Din
Speaker Size Front: N/A
Speaker Size Rear: N/A
Speaker Size Subwoofer: N/A
When installing a new radio you won’t need a mounting kit or antenna adapter for this vehicle, but you will need the BMW Radio Removal Tool
REQUIRED PARTS FOR AFTERMARKET RADIO INSTALL
RECOMMENDED TOOLS FOR THE INSTALL – SAME ONES THE PROS USE!
– Dash Removal Plastic Pry Tools
plug either the aux or the rcas into the back of your new aftermarket radio depending on what type of audio input they have. Then cut off the other end and splice into the following wires at the 14-pin connector found behind the radio:
to easily get the job done.
they work great and are an excellent bang for the buck! Or the 
if you want to replace your OEM tweeters in the dash as well.
