Well I tried the blink tool... but it was a no go for me.
At Radio Shack, I couldn't find the banana plug set (274-271c), so I bought 274-721c, assuming maybe the original was just a typo (2-7, 7-2).
Anyway, the banana plug set is way too big to fit into my connectors in the 95 C280. I don't know if I have the wrong banana plug set or if the system has different size openings?
Now for question two... you say to plug black into number 1, and red into number 7... which hole is one, and which is 7?

Thanks..!

(If it'll work at all on my C280!) ...I can already get codes (climate control) via the PBU.... will I be able to pull ABS, SRS, or other codes, besides just the Climate Control codes? If no.. then my work is pointless!

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2006 E350 w/ 155k miles (Daily Driver)

Previous:
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)