tach and odometer stopped working

Took my 1987 S4 to a specialist garage to have a Power steering leak fixed, they replaced a hose and cleaned up the area. We noticed that the tach was not working they asked I bring it back another time and they will see if they did something to it. Havent had time to do so they are 35 miles away) Since then I have discovered that the odometer stopped working at the same time plus some of the various system warning lights on the Tach side of the dash no longer work. Is it possible they did something to cause all this at once???

Check the wiring to 14 pin connector under the hood on the passenger side.It has a tendency to deteriorate. I have a 86 that I am rebuilding the engine I found the wiring harness that runs from the 14 pin connector across the front of the engine was burned, before I found this I had the same problem. I replaced all of my instrements with late model counterparts.

I just had the same thing happen on my 89 S4 after I replaced the power steering lines. All fuses are fine. It was working fine before I started and now tach, speedometer, and digital dash is dead. Interior lights are fine. There was pressure to the alternator wires while setting up a hanger for it and upon removing that prior to bolting it back up. Could that affect the digital dash? All of my wires are solid going to the 14 pin connector. I had the engine out and inspected the harness earlier this year. I also had the dash out to replace a vent controller so I know all pod connections are solid. No digital dash issues for months until I tackled this. Did the original poster ever find the source of the problem?