Bernie Steffen

New Member
1985 GN Digital dash Booooo Anyway on the dash the lights for turbo boost. I know not accurate not even adequate. But I have one yellow light and one red light right below it. The red light only comes on when you get after it. I can"t find anything about it in the service manualexcept it says something about a less efficient light. I was worried it might be a knock alert or something like that .. any information appreciated. Bernie
I would guess that the vacuum line from the MAP sensor is open. If the turbo doesn't boost look for an open vacuum line from the block(firewall side). Brad
there will be two sensors most likely on the right inner fender,that where
they where on my 87 t and 78 turbo. it will have the vacuum lines attached
to them,red is high boost ,yellow lower boost. the hot airs can overheat
at full boost if you have it down long enuff(like five miles striaght).
shouldnt have anything to do with knock.
if you look at the boost gauge on other turbo cars you will see that
the lights turn red around 10 or more pounds of boost.
same thing just a factory "saftey" thing.

here's the scoop about the 2 lights:

1. the lights on the digital dash are the equivalent to the tach-LED-boost bar on the anolog dashes...the only "safety" thing about it is that w/o a boost gauge (the lights being it) it gives you a baseline for where the boost is at. IT DOES A HORRIBLE JOB...DON'T rely on these lights when adding mods.

2. the yellow one comes on around 3-4 psi, and the red one comes on closer to 10 psi.

3. as far as the location, there is 1 vaccuum line routed to a black and silver sensor on the pass. side fender, it's directly over the tire near the power antenna plug. I destroyed one when my factory turbo took a dump and sent oil all through my vaccuum system. When I got a new one (about 3 yrs. ago) it was around $40 bucks from GM. There is a set screw on it that I need to adjust, so it might not be set up for your car, right out of the box.

4. The lights have NOTHING to do with knock.

be careful....HTH