As I understand the bulb failure system to work, it checks for a difference in resistance flowing through either side of the brake lights, and if one side has enough of a difference, it lights up the warning light.

I also understand that lots of people that add a 3rd brake light to their older 240s just tap one side of the car, but this causes a resistance imbalance, which causes the warning light to come on when ever the pedal is touched.

Here's my idea...

If I were to tap both sides of the car using 2 bulbs (one for either side), wouldn't that keep the resistance the same across both sides if I use the same length of the same wire, and 2 identical bulbs?

Also, wouldn't this set up still allow the bulb failure sensor to still function correctly (since if one of the 4 bulbs on the circuit goes out, the light would come on)?

The only thing I can see that would keep this from working is if the Failure sensor has a certain resistance it checks for... So if it sees a resistance above a certain amount, even if the same on both sides, it would cause the light to come on... but I don't know if this is the case.

I realize this post is a bit fragmented, but it's a thought I just had...

Anyone have any reasons why this wouldn't work?

I'd be adding this to an '80 245 DL, if I do decide to do it at all...

Thanks as always.
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If you listen to the radio in Portland, OR, you may know me as "Portland's Favorite Soul Brother!"