I have a 3.0 mk3. Been off the road for a while used it a couple of times been fine. Used it the other day and smoke started coming from behind the ammeter and it melted the plastic coating on the spade connector on the back of it. Anyone had this problem before?
Never had smoke but the Ammeter did die on me once. Lost all connection and the car would not do ANYTHING! Of course I was 40 miles from home too so it took me about an hour to figure out what happened and connect the two wires to each other to get the car running! Then I had to find someplace in the US to get a replacement. It's been 25 years and I forget where the replacement came from now. The joy of owning old cars (of any make).
To confirm this, check what the needle is doing. Hitting the end stop of course confirms the short. It may of course be an intermittent short. They can be very hard to track down.
If the needle is moving but not hitting the end stop, then you most likely just have a poor connection at the back of the ammeter. However the spade connector and wire will likely now be annealed and therefore too soft.