I dug out some grommets that came with the car, and I believe that the grommet for where the lighting and horn harness goes through the frame is 186 997 07 81. This is shown in the EPC as Qty 1, but listed twice (!).
Chuck,
as Jonny B. described it in the 250SL/280SL spare parts list (Edition C) this part is listed twice:
1. on p. 173 as item #41 in Table 21 and is used 1x on LHD manual transmission cars only.
2. on p. 177 as item #74 in Table 21 and is used 1x on RHD manual and auto transmission cars.
I have just finished doing the wiring on my 280SL while visiting Joe Alexander and I found this grommet on my 280SL automatic also - but perhaps at a different spot from where you found it.
Mine was after the split of the main harness (driver side branch) into to the part to the left head light bucket and the right part going through a hole in the front engine compartment wall and then across the front nose to the right head light. The attached photo shows it on my 230SL - and the 230SL spare parts list indeed shows it 1x for all versions.
Johnny, you are absolutely right. the parts manual is dismal when it comes to location and part numbers for all the rubber grommets. This would also be a good addition to the technical manual.
Joe Alexander and I are working on a "road map" for the wiring harness in the engine compartment with all part numbers for grommets,clamps and clips holding it.
We also plan to include the color coding for the various wires in the plugs that need to be taken apart in order to install the big main grommet on the fire wall. The problem with this project is that this will be for an
early 1968 US version 280SL car with automatic transmission. 1969 and 1970 model year cars will require a different road map.
Took me about 7 hours
to accomplish this "minor" task of sliding the big grommet along both harness strands (on right and left fender) to its location on the fire wall, I had the feeling it shrunk along the way.
No wonder so many are split and then inserted.