I've been working to rebuild my trusted '86 190d 5 speed since a minor front end collision so I can sell it to someone who will drive it like it was meant to be driven (was my daily commuter for the last 2.5 years, but sadly it's been replaced by a VW TDI while being repaired)

The last bit of work that needed to be done was to have my shop find and fix an electrical short that was causing my front passenger side and rear driver's side windows not to work--I tested the motors and regulators behind the switches, and they worked just fine. My shop called me the other day and said they had found the short and replaced some of the wiring in the door jamb ahead of the switch for the rear driver's side window and everything now worked fine. When I went to pick up the car, it started up just fine--glow plug light came on, and everything was normal. But, when I tried the windows, the fuse blew.

After another hour or two in the the shop, I was told that they had to remove the fuse box and had found a crushed and intermittently shorting wire that was causing the problem (which was in fact the case b/c I had seen the smoke coming from under the fuse box when they were diagnosing the problem, and they showed me one of the burned up shorted wires).

So when I went to pick it up, the windows worked, but it started a bit rough - 75 degrees outside. I drove it a short distance and shut if off. When I went to cycle the glow plugs to start it a bit later, the glow plug light didn't come, but because the engine was warm, it started....I checked the fuse, and it is fine....

This morning I went to start it - 50 degrees outside - and the glow plug light didn't come on and I couldn't get it to get going and turn over. I was thinking that even if two of the plugs had gone bad - preventing the light from coming on, that it would have at least gotten going (albeit roughly) on the three cylinders with good plugs--which makes me think the circuit is completely dead.

So here's the question - is there a connection between the glow plug circuit and the fuse box and/or window circuits such that my shop working on the windows and fuse box could have killed the glow plug circuit, or is this just a "coincidence"?