Extra wiring through firewall?

[ctaylor738]

I am getting ready to secure the wiring harness to the firewall in the 280SL project (1970, US, automatic).  

It has some wires running through the firewall grommet where the speedo and tach etc. cables go.  These wires look very official and most (see below) tie into the main harness.  They are in three "bunches" in sleeves together.

Bunch 1, 2 wires.  Brown/Black and Red/Black.  End in a two-pin female connector.

Bunch 2, 4 wires.  Red/Green, Brown/Black, Black/Red, Brown/White, end in ring terminals

Bunch 3, 2 wires.   Both brown, both cut (that doesn’t help), end in ring terminals

Bunches 1 and 2 are in the group of wires that runs to the high/low beam switch on the floorboard.  They separate from the switch's wires about two inches from it.

The Red/Black wire in Bunch 1 has connectivity to Fuse 3, no information on fuse chart or wiring diagrams.

By the length of the wires, it looks like they would terminate in the relay area of the left fenderwell.

Picture attached,  Yes, I am planning to install a new grommet.

This weekend at Starfest, I  spend some time inspecting that grommet, and the main harness’ grommet on three other 113s.  None had these wires coming through.

Thoughts/ideas?

[Leester]

I can take a look on Saturday (earlier if the rain abates) to see what mine looks like although I may not be much help since engine and all other parts are out of the engine bay - acquired the car in that condition - but I could at least confirm if I have same wires. Mine is a 70 71 ish.

[Leester]

OK - I too have i bunch the same as your first which is a brown/black and red black but mine end in separate ring terminals.

I also have two separate bunches of what I assume are ground wires, 1 bunch is two wires ending in one common ring terminal and another bunch is 3 brown ending in a common ring terminal.

I also have two wires each ending in separate ring terminals that have the original black tubing insulation that I have not bared to see the colors of the wires within.

I'll look again tomorrow to see if I have the same as your bunch 2, if I do though they will end in a connector since i have no more wires in that area that end in ring terminals.

All of these wires come through the firewall grommet near the mounting block for the master cyl and stretched out straight they extend to about where the subframe mount is.

I checked my wiring diargrams. I do not have one for the SL but the wiring diagram for a 280Se looks like your bunch 2 might be for an add on AC.  Of course you don't have a 280SE but that's the closest I can come to finding any reference.

[scp]

I have a more basic question to which I have been unable to find the answer to date:

What wires / cables / pipes / ... go through each hole in the firewall?  Also, what specific grommets go in each firewall hole?

years past I looked at Bob's pictures (on Picasa Web Albums) of his 280sl undergoing restoration, but they appear to have been removed.

Any help would be greatly appreciated.

Cheers,
SCP

[ctaylor738]

After some more  investigation, those wires don't go through the firewall.  They are the wiring for the automatic transmission, and they route through a hole to the left of the the kickdown switch on the floor.

As to the question as to what wires/cables go through where on the firewall.  Looking at the firewall and moving right to left:

Main wiring harness, grommet 111 997 13 81
Hood release and washer hose, grommet 111 997 23 81
Connector for trouble light
Speedometer cable and oil pressure line (lower small hole), grommet 111 997 07 81
Tach cable and temp gauge wire (upper small hole), grommet same as above