I bought what looks like exactly the same kit from some guy in Germany who had sold a ton of these. Installed in about 30 mins in my wife's 1990 300SL. The original remote key didn't come with the car, and I didn't feel like paying the $200 each the dealer wanted!

I just hooked it up to the locking pump in the trunk (was about 3-4 wires if I remember correctly) and it worked.

BUT then I got smart and went to the dealership to talk to them about keys. They sell three keys for the 1990 car we have:
A. Remote including metal key 'blade' as they call it
B. Standard key (looks like the 80's MB keys)
C. Key blade replacement only

I bought item C and it fit just fine into this remote. When you flip out the key blade, you'll see a little screw or pin that needs to be removed. Then put in your newly purchased blade from the dealer and you're good. The groove in the key blade from MB didn't match the location of the remote pinhole, so I couldn't put the screw back in. The thing is wedged in so tight, it won't move (I was planning to superglue it, but it's *really* stuck in there).

I think the key blade cost $35 Canadian at the dealership and was ordered to match the car. Most people think this remote/key was original to the car and it certainly looks like it!

Hope this helps...

Neal

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'83 300SD 335,000km (207k) mi SOLD
'87 560SL 163,000km (101k mi) SOLD
'86 300SDL 356,000km (220k mi) SOLD
'92 500SEL 250,000km (155k mi) SOLD
'90 300SL 140,000km (87k mi) SOLD
'01 S430 260,000km (161k mi) SOLD
'03 SL500 167,000km (104k mi) SOLD
'07 S550 4MATIC 235,000km (146k mi) SOLD
'07 GL320 CDI 4MATIC 348,000km (215k mi)
'13 GL350 BlueTec 4MATIC 170,000km (105k mi)
'14 SL550 72,000km (43k mi)