Just had a 2000 Beetle TDI with 200k on the clock cut out on the road. The first time it quit, all the gauges (including the speedo) dropped to zero. It came back after a couple of seconds, and the oil alarm sounded. My wife and I turned around and started heading home, but we only made it another mile before it died and stayed dead.
After towing home (with my wife threatening to call CarMax and get a GOOD car every mile of the way), I checked it with VCDS, but couldn't connect to the ECM. Looking online, I found the thread about relay 109. I did not notice what color mine was, but just wiggling it was enough to bring the ECM back to life and let me read the codes (there weren't any, except for an "intermittent ECM communication" error on the CAN bus). I pulled it and noticed that there seemed to be some slight burns on the pins, like you would expect if it wasn't making good contact. I polished up the pins, smeared silicon dialectric grease on them and reseated it. I didn't note what color my relay was (the dash is back together, now, and I'm lazy), but the "109" was printed right-side up, so I'm thinking it was an original. If it ever cuts out on me again, of course I'll replace it, but I really think that a bad connection to the socket is as likely as a bad relay.
I haven't seen it referenced anywhere, but I'm wondering if that relay also supplies the air bags, because that system showed intermittent low voltage also.
