300E console/reverse light cable
 

I have a '86 300E with manual transmission. The reverse lights do not work due to a faulty cable between the switch at the base of the shifter and the transmission. I am attempting to replace the cable, however, its becoming more work than what I expected to accomplish.

I removed most of the console to access the cable (see photo). The cable appears to be bundled to a group of other wires as it enters the transmission tunnel. The next step would be remove the console completely to access the cable. Before I remove any further components I am checking here for any advice.

Another issue is I discovered a cut wire which would connect to the cigarette lighter. The lighter works but I cannot explain the cut wire or what it does.

Also while I am at it I have a new parking brake cable. Although its been awhile since I researched, I think the console needs to be removed to replace it.

If you are looking for where the cable goes to the transmission don't spend a lot of time as it doesn't do that. I can track where it goes for you on a 5 spd parts car if you need that, but not until the weekend (its not stored here). let me know, console is already out of it.

Unsure about the lighter wire, but on a 190D the lighter 12V (ignition controlled) continues on to feed the glove box light.

It wraps around by your feet, goes down the driver's side of the center tunnel, inside the console, pops through the tunnel beside the driver's seat IIRC.

Thanks Hanno, I most likely will not have time until this weekend to pick where I left off. If you can track the cable, I'll be looking forward to your response.

Sorry, I was talking about the parking brake forward cable.

Thats fine, I will concentrate on the parking brake cable and do the reverse lamp cable later.

I'm good with the front parking brake cable but still need advice on where the large plug end of the cable for the backup lights connects under the console.

OK, took a look....small 2 pole connector at the backup light switch, cable routes forward and is tied to others on upper left side of console, comes out of console forward left side, larger plug socket is above your right foot. After removing enough "stuff", its at the end of a line going forward and slightly down from the ignition switch. I'm unsure if the connector is visible when the console is in the car. Its mounted on the side of the heater assy. Enjoy!:D

Thanks Hanno, with your help I found the connector under the dash and replaced the cable. I hope it was not too much trouble for you to check this out for me.

Your support is deeply appreciated.

865, anytime. Car is already half apart, interior gutted so it wasn't hard to follow. Is the yellow pigtail in your picture used? I don't remember seeing that (but didn't look for it either). Do your reverse lights work now? I had an issue during a conversion that turned out to be tight mounting of the switch.

The new cable is the correct replacement part for the old cable, I double-checked. The pigtail was not used, I have no idea of its purpose.

Bad news is the reverse lights still do not work. I checked the new switch and new cable for continuity and they are good. The reason why I replaced the original cable is there was an intermittant connection. Sometimes the reverse lights would work, other times not. When I removed the shifter boot and wiggled the old cable the lights would work.

I checked the bulbs and they are good. Connection under the dash is tight. Next step is I will check the wiring schematic and perform more troubleshooting.

Hanno, thanks for following up.

When mine was acting up, the switch itself was binding due to pressure from the connector and harness. Minor rerouting solved that. I assume yours is mounted correctly so that the linkage activates it properly?

Yes, the switch is mounted correctly. The switch and new harness to the switch were checked before installation. Unfortunately, there appears to be a power issue since I have no power at the connection under the dash. I checked the fuses and other things function that share fuse 7. I have been working a little bit at at time and really need to study the wiring diagram.

Previously, the backup lights would work only when the old cable was "wiggled" at the switch. With new parts I am a bit bewildered to have nothing at all now.

I do not give up easily but the 300E passed inspection without backup lights and I gave up troubleshooting for now.

Still cannot find the cause of no signal to the harness. The car has been put back together and I'll revisit this issue when it gets warmer here.