finding pinout for shared ground input

Hello, I am trying to determine the pinouts for a 6 pin "DIN" input adapter on the stock amplifier in my 1993 Volvo 240 wagon. I've heard the 6 pins are LF+, RF+, LR+, RR+, ground, amp turn on. How can I determine which are which?

I tried a voltmeter to the radio's 6 pin line-level output to the amp, hoping I could adjust fade/balance to send signal over one speaker line at a time. I connected the negative probe to the radio's power/control harness ground wire, then probed each of the 6 pins. I got a 9V signal on the center pin but nothing else. I tried the negative prove on the center pin and got nothing on the others.

Or, could I try connecting my hacked RCA-to-speaker-wire converter to the amp input to see which pins give me sound? Might I hurt the amp by sending input down ground or amp sense? I'd use an iPod to test; could I hurt that too?

Ultimately, I'm trying to integrate an iPod with the factory system. I'll install a PIE MPSS4 source switcher between the radio and amp to give me a second input for the iPod. Then, when I turn the radio off, the switcher will get signal from the iPod. It's just a fun project that I haven't seen anyone do (because it's pointless; I should buy a new amp and headunit), but it's a fun challenge. Thanks for your help.

I've cut din plugs quite often on those older volvos, unfortunatly I do not remember the color code.

What I do is send 12v on the remote wire, then take a cut rca end, ground the sheild and touch each leftover 4 wires one at a time to find which is which. You will not hurt the amp sending audio to the amp..it is designed for that, if there is too much voltage you will notice that problem by ear and need to deal with it.

You can also send a small voltage to the signal inputs with a AA battery (1.5v) quite safely..listen for the popping sound from each speaker. touch the - of the battery to the shield or ground wire and use the positive side to each leftover wire.

Good luck.

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Custom Audio
Lynbrook NY

ASE/MECP master certified

 Also, don't use the ipod to test, I don't know if grounding the outputs will hurt it..but the amp will be fine. The center pin with 9v is the remote. You can find the ground using a meter..set to resistance, ground one probe and touch the other to the pins one at a time..when you read a very low resistance on one of them, thats the ground.

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Custom Audio
Lynbrook NY

ASE/MECP master certified

Ok, I will test the audio with a battery instead of an iPod. Thank you for your help. Now I can finish this silly but fun project.

wiring diagram

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just watch out because on occasion the manufacturer may change the color codes for various reason so use that as a starting point and as custom audio said, test the wires with a battery and listen for a "pop"

For the record, I determined the pinouts for the 1993 Volvo 240 wagon stock stereo WITH SEPARATE amplifier. The instructions linked above are for the radio with the built in amp.

In back of the radio is a 6 pin DIN socket. The pinouts to the amp are:
1 = Front Right
2 = Front Left
3 = Rear Right
4 = Ground
5 = Rear Left
6 = Amp Sense - 12V

To be clear, the pin numbering matches the female connector (radio). Pin 1 is at 2 o'clock, pin numbers increase by going clockwise until pin 5 at 10 o'clock, with pin 6 in the center.

I wired the grounding shroud of all four RCAs to pin 4. It seemed to work, until my poor solder job crossed the 12V line with the ground line and essentially fried everything connected to it. But that's in another thread.

Don't bother making your own cable. Just ask the guys at Quick Brick Motorsports to make one. They offer both 6 pin male to RCA, and 6 pin female to RCA adapters for most 90's Volvos. Check the QBM product page

Good luck.