Ballast Resister Wireing

[tel76]

I understand that with the introduction of the 280sl there was a wire introduced into the system that took power from the starter solenoid to the coil side of the ballast resister,this enabled the ballast resister to be bypassed in the starting faise (not on transistor models).
Can someone inform me if the wire comes externally from starter or is it inside the loom,if it is inside the loom where does it exit?
The coil is part# 0 221 102 036 together with a Bru resister W7-09 and when i stripped it down 2 years ago the ballast resister was bypassed (both wire from the loom and the wire to the coil were on the same terminal).

[Naj ✝︎]

Not all 280 SLs have this bypass.
I would first check the starter to see it has the extra terminal which is energised when the starter is operated.
Next the wiring loom?

Naj

[tel76]

Hello Naj,
I thought that at least one of our members would have responded with this information,do i take it that it is not fitted to the 280sl?
If you look at the wiring diagram on a 280se/8 and 280sel/8(fuel injection)the wire is shown coming from the starter.
I do not think you need to go back to the starter to make the connection,on the rhs of the engines sump there is a connecting/junction box bolted to the sump it has two wires in and two out one is thicker than the other and supplies the vehicle with power,the other is the wire from the ignition switch to the starter, if we take a wire from this junction  to the ballast resister we will have carried out the required modification.
As i am not in a position yet to fit/connect the battery i cannot say if the above is correct but when i connect up the battery it will be the first thing that i will do.

[Naj ✝︎]

Hi, Eric,

I believe that the ballast bypass was not fitted to all 280 SLs, maybe just the ones from '70 onwards.
I also believe this change came in with the later higher HP starters. The solenoid on these have an extra terminal which is energised under cranking only. Hence the suggestion to start by looking at the starter first.
In the picture the new starter on the left has the extra terminal.
If you do want to fit a bypass to an earlier car, have a look in the Tech manual under coils.
One of the coil pictures supplied by Bosch shows a wiring diagram showing how to acheive this with an additional relay. We have done this to a friends 230SL and starting has much improved, still using the original  'black' coil with a 0.9 ohm ballast.

Hope this helps

Naj

[hands_aus]

here is a topic about modifying the ballast resistor wiring during start up

http://www.sl113.org/forums/index.php?topic=4240.0

[tel76]

I did read all that.
On the rhs of the engine there is a terminal block with one large and one small terminal ,take a wire from the small terminal to the ballast resister,this is what i have done.
I have not tested it yet as i have yet to connect the battery.