My '90 s4 is missing relay no XXII - Listed as as ezk igntion relay. But the car works fine. How and why - and should I replace the relay? I put in a fresh air blower relay by mistake (Doh!) and the car wouldn't stop running even with the key removed. I'm not doing that again. What does this relay do and how can the car run without it? Or is it optional for some reason? Any help would be greatly appreciated.

 

Can't help on your relay, but I had a similar experience - I noticed the fuse for the driver's seat motor was missing, so I put one in. Hadn't noticed the seat not working, but why not?
Went out for a drive, returned and turned off the engine - which didn't stop. Pull out the fuse, engine starts and stops as required. Passenger seat (has fuse) runs without the ignition on. Driver seat only moves when the ignition is on.
Decided that its really just fine that way, there's only so much fun you can get from crawling into the footwell fiddling with fuses.
I've had Citroen's and Fiats, and their electrics are only marginally more peculiar than a 928.

 

Sounds like both you guys have had PO's with Creative Electronics Fiddling Syndrome (CEFS).