No check engine light, i replaced some vacuum lines a day earlier, needle responded normally for 24 hours, coasting down hill noticed needle hadn't fallen back to black. Is this gauge electronically, mechanical, combo controlled?

I wish I could be the helpful poster lile so many of you are, I check the list every few days to see what other 850 owners are dealing with and my lack of experience keeps me from being helpful. I do appreciate the suggestions. I wanted to post the details of the prob and solution for any future searches that might help others.

The turbo gauge hose comes out of cabin WITH the hood release cable, they are side by side and it even looks like the same size and kind of cable as the hood cable, however the tubing is not the softer, larger, more pliable hoses like the ones I had been replacing, it is thinner and shiny black plastic feeling. Its easy to find if you just find your hood cable release right next to the fan shroud and latch ofcourse. There are 2 normal looking black vacuum lines and then there is a white and black tipped hose , i dont know, but think they are coming from the wastegate or some turbo related valves, the gauge line ducks under the air intake scoop that is infront of radiator, there is a connection piece of the normal soft thick hose material and then it continues on with the thinner plastic. In my disassembly of airbox and air intake hoses i inadvertently pulled the hose apart, it is under the air intake scoop and not visible unless you follow it with your fingers, plugged it back in and voilla. gauge reading normal. The turbo was working fine while the gauge was not working.

Thanks again for saving me from a trip to empty my wallet

Also check the vacuum line inside the car. It goes from the gauge down by the hood release handle before going through the firewall. The gauge is vacuum pressure only.
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95 854T, 88 780, 88 245

Definately recheck your vaccuum lines. Given the recent history, that's got to be the problem.
Mark '94 855T

On my old 740, I had the instrument cluster out for replace the tachometer. I picked up a used tach on ebay for $10. that also had a turbo gauge although my 740 didn't have turbo. The turbo gauge had a small nipple on the back to which would be attached a small line so I'd assume the gauge is vacuum or pressure regulated. It had no electrical connections of any kind.

bl