Y'all,
The stock backup lights on my 300td were pretty much useless (both sides smashed beyond repair), so I had to replace them. I really didn't want to spend
$80 each for them, so I searched for some aftermarket replacements.
I wanted to install a
"utility" type of light as I'd done for backup lights on my motorhome, but all of the ones I could find were way too big. Almost every fog light out there is way too big as well, but I finally found one that would fit: the
Peterson Manufacturing V557-2, at $30.95 when
I purchased the kit from Amazon in January (it's $39.99 as of this writing). The lenses are glass and are bonded to the reflector, so they should not get stained by the soot and soot shouldn't be able to sneak in. They're also short enough vertically that they don't hang down below the bumper.
To install them, I drilled the stock backup light brackets in the bumper, next to the hole the stock lights mount to. The stock backup light brackets have a ridge that mates with the back of the stock lights, so to get the V557-2 brackets to fit flush against the stock bracket, I cut the V557-2 brackets, removing 1" or so in the middle. However, once I had them mounted up, the lights sat too far inside the bumper, so I added spacers under the V557-2 brackets; that meant that I didn't end up needing that cut in the V557-2 brackets, as the spacers were taller than the ridge on the stock backup light brackets. I had planned to reinstall the rubber surrounds, but they wouldn't have fit well without serious cutting, so I decided to save them in case a subsequent owner cared to go back to stock backup lights. I think they look fine without the surround anyhow.
For the wiring, I installed a relay next to
the high beam relay I installed earlier, using the same fuse as the power source. The stock backup light power wire coming from the switch at the shifter is now the trigger wire for the relay. I considered running dedicated backup light wires from the relay (and had started on that), but decided to use the stock wiring for now. Since these are just backup lights, they won't be on for long durations and I'm not concerned too much about any possible voltage loss in this case. To connect the new lights to the chassis wiring, I used the pigtails off the stock backup lights and connected them to the new lights with crimp-shrink connectors.
While the fog beam pattern obviously isn't optimal for use as a backup light, they work great, and at less than 1/4 the cost of going with the stock units, I'd do it again. Of course, offending MB purists by installing non-stock parts is bonus!
-Shawn