Early W124 sedan quickie stereo wiring

[sixto]

I didn't see this info in the archives so I'll post for the next person. I believe these notes are valid for 86-89 W124 sedans. The 90-up cars have door speakers, external amps, CD changer wiring and other complexities.

The mechanical stuff is here so I won't repeat - http://www.peachparts.com/Wikka/W124Stereo

Contrary to these instructions the mirror switch in my car stayed in place. The fader lifted with the wood panel.

With the stereo out, you'll see the following wires:

- 4 wires into a 4-pin connector
- 2 pairs of wires into 2-pin connectors attached to the stereo
- 2 pairs of wires into 2-pin connectors looped into matching connectors
- 1 wire into a spade connector
- 1 coaxial cable into an antenna connector
- 2 wires into a 5-pin connector

The 4-pin connector has wires for power and ground:

- brown = ground
- black with yellow stripe = switched +12V
- red with white stripe = continuous +12V (clock, station presets)
- gray with blue stripe = variable to +12V dash illumination

The 2 2-pin connectors attached to the stereo have wires for the rear speakers. You can touch the wires to a 1.5V battery to see which speaker pops.

One wire pair:

- black with green stripe = right rear speaker (+)
- black = right rear speaker (-)

The other wire pair:

- black with red stripe = left rear speaker (+)
- black = left rear speaker (-)

Note my loose use of terms. These wires actually go to the fader but the rear speakers are disconnected from the fader so it's as if they don't exist.

The 2 2-pin connectors looped into matching connectors were difficult to pry apart. One came off with persuasion, the other came off leaving the contacts in the socket. Note - the FSM shows these wires going to the rear speakers but that was not the case in my car.

One wire pair:

- black with green stripe = right front speaker (+)
- black = right front speaker (-)

The other wire pair:

- black with red stripe = left front speaker (+)
- black = left front speaker (-)

The wire with a spade connector controls the antenna. The antenna switch beside the rear dome light switch will continue to work as with the original stereo.

The 2 wires into a 5-pin connector wasn't attached to anything. I didn't use it.

As mentioned, this is a quickie job. The rear speakers run on their own but the front speakers run through the factory fader so the fader has to stay in the loop. I suppose you can relocate the fader you no longer need to adjust so you can use the switch location for something else. The new stereo's fader should work as expected.

Sixto
87 300D