So I have kind of a weird issue, at least it's weird to me. So I have a 1991 Convertible (completely stock) with roughly 100k miles on her. The issue is that the Tachometer won't work at all until after the car has been warmed up, now it takes about 5-10 minutes of driving for it to warm up in 0 degree F temperatures. Usually once the coolant temp gauge hits the half way point then the tach seems to come on. This issue started literally the first day it hit Zero outside.

Now, I don't really need the tach to drive, as I've learned how to drive on an old VW bug that didn't have a tach. So it's not really a big deal, but it's something that I would like to fix.

I haven't really done much trouble shooting myself as it's been ***** cold outside. But now that the weather is calming down and temperatures are rising, I think I'll be able to find some time to look into it. I've played around with the lead wires and made sure everything was tight such as the coil pack. Anyways, what do you guys think?

 

Most likely it's the gauge itself.

Although it's an electronic gauge, there still is a mechanical component...maybe hit it with some electronic contact cleaner, see what happens. If that fails (or even worse, renders the gauge completely dead), you've lost little because the next likely culprit would be the circuitboard and at that point you're probably replacing the gauge/cluster anyway.

I have a couple of S5 clusters if you need one.

 

Yeah, it looks like I might need one, even in warm weather it only turns on once the car warms up to operating temperature. I've played around with a few wires, and can't seem to find anything out of the ordinary, without pulling the entire cluster that is.

Unfortunately I only have two extra clusters, and they're S4 NA and Turbo... I might have to take you up on that offer Clokker... I'll let you know though.