Hey guys.. I really need some help on figuring what I screwed up and how to fix it.. If it's even possible.

Basically, my 2006 S350 airmatic seems to have failed (pump doesn't seem to activate)

I figured I'd start small and check fuses/relays.

​​​​​​In the past, I've successfully diagnosed a bad relay by swapping it out with another matching relay

This time, the relay in question for the air suspension pump did not have similar ones to swap out. I thought I would try find a matching relay from my other Merc (2013 GL350 Bluetec)

Here I quickly learnt that despite the same shape, size and amount of pins on the relay and mostly matching numbers, it does not function the same.

Upon dropping the relay into the fuse box of the S350, it sparked and heated up. I quickly pulled it out but the damage was done. Theres still a decently strong metal burning smell coming from the fuse box

I ran another scan (attached) which shows a whole list of electrical problems, primarily seem to be no CAN message received across multiple modules (Transmission, Electronic parking brake, and a few others).

The car still starts and runs, and engages in gear but very hard (I suspect it's in limp mode), and the reverse camera no longer engages in R.

The electronic parking brake engages and disengages as normal by the sounds of it.

Pic of the relays (green is correct one from S350, yellow incorrect one off 2013 GL350). I don't even know what I'm looking at the on the diagrams, I'm very novice in terms of understanding electronics hence why I made this huge mistake..



I returned the relay into the GL, no issues, relay seems to be working fine, so something else must've fried.

The circled pin has burn marks. Another angle, the burnt pin is noted as (3)



Looking through WIS, I found some wiring diagrams which I barely know how to read. The green box is where the wrong relay went in. Full diagram Pdf attached.



I don't know what to do next.. Any ideas?

Thanks guys..

 

on the green one - its not an earth symbol – that’s a diode, so most likely for powering an indicator light and prevent back feed

I guess u trashed the circuit to energise the relay

normally the big orange 40 Amp fuse pops when the compressor has been working too hard - always check the THREE level sensors FIRST - they snap or bend leading to the compressor trying to achieve strange things till it gets tired