72 280se - Need help define these relays

[Bdub03]

Hello Folks,

Working on an engine swap and am trying to define what components use the 3 relays listed on the driver fender. Giving pin 30 power to each relay, I can't quite seem to find out which components they go to and my Haynes manual does not cover these. Hmm?

Original engine is a M130 MFI

Any help is appreciated.

[Benz Dr.]

The front one should be a cold start valve relay. The middle one should be your injection pump starting aid relay, and the back one should be your wiper relay.

[Bdub03]

Thanks. I couldn't find it in the tiny schematic but will pin out colors tonight once it gets cooler.

[Bdub03]

correct. Front and middle pertained to the engine harness and were pulled. Thank you The rear relay however has nothing to do with the wiper and has no coordination in my Haynes manual either.

Pinning out, is Normally closed (87a) to the passenger occupancy sensor and the dash light. I'm missing the 86 lead on the relay so I'm not sure what would disconnect the occupancy sensor. Considering soldering 87a and 30 together and deleting the relay.

Thoughts?

BTW, M113 is wired completely, and all accessories are working with the W210 EIS. I'll share more details later if you're interested

Normally closed Relay pulled into the interior (was under the hood), missing 1 pin :-/


Green/Black wire illuminating pass seat light. Black/Green wire going to seat occupancy sensor?

[Bdub03]

Self resolved...

Page 169 in the Haynes covers the US only Seat belt warning system which includes a relay for the buzzer ONLY activated while the transmission is in drive modes. Would make since why that pin is missing, I've pulled the existing trans harness. I will loop gnblk <->blkgn and call it a day.

Thanks again, sometimes its healthy to post than stew and over complicate