I know this has been posted before, the issue is that no one describes how they actually solve this problem. At least not that I can find, and I've been searching for a few days.


Installed a new radio on my Belgian made 1991 740 (B230F), replacing the factory original that was still in the car. I cut the wires instead of using a harness converter not realizing what I was getting myself into. I've done this before on my 91 and 93 240's, but they already had aftermarket radios and were plug-and-play situations.


My first try at installing, the headlights stayed on no matter what. Even with the keys out of the ignition. I realized what I had done, and tested the 2 white/yellow wires on the car to see which was live. I insulated the non-conducting one, and wired the other to the 12v Accessory wire (orange).


That solved the "always on" problem, but gave me day-running lamps. They are on whenever the car is on, regardless of where the light switch is turned to, or if the radio is on or off.


I've tried several configurations and either get no reaction at all (only parking lights, signals, and brights), or the headlights always on. Obviously this isn't the end of the world, and an argument could even be made for safety of always having headlights on. But I want to fix this.


The radio side is the common current set-up, 12 wires, all clearly defined for their purpose. What do I need to do with the 2 yellow and white wires to get my lights working as designed again?


Issue 2: I have read that I have to bypass the stock amp to get my rear speakers to work. Is that true? Or can I use the amp? I don't have an adapter from 6 Pin DIN to RCA, but I know how to deconstruct the DIN cable and wire it to the RCA/radio speaker wires. If it's better to bypass the amp, that's fine too.


Any help is appreciated. Here is how the radio is currently wired to the car:


Radio black wire to Car black and dark gray wires (ground, matches factory config)
Radio red wire (12v accessory) to Car orange wire AND Car yellow/white wire
Radio yellow wire (12v Constant) to Car green/red wire
Front speakers (Radio white and white/black to Car brown and brown/white; Radio gray and gray/black to Car gray and gray/red) are working fantastically
There are purple + and - and greenish-blue + and - that are obviously for rear speakers, along with an RCA pre-amp input on the radio.

 

the two white-yellow wires are supposed to be connected together, NOT to the orange wire. gad only knows why, but thats the headlight control circuit going from the headlight switch to the headlight relay coil circuit, for some reason it stops off at the factory radio (which probably used them to control the display brightness or something?).