Some info from the gnttype.org archives...
Here's how you test: There's a brown connector on the passenger side fender well right next to where your MAP sensor would be (if you had the analog dash). It has two wires; a black wire and black/white stripe wire. The connector is plugged into a switch assembly that is plumbed to the vacuum line. All the switch does is ground either one or both of those wires depending on the boost level. I think it's 4 PSI and 10 PSI. You can test the wiring and bulb by grounding each terminal. When both are grounded, both lights should light. -John Spina
We repair and upgrade the Regal digital dashes, and they're easy to remove (11 screws, leave the odometer in the car) Actually it's simple, can be done in less than 10 minutes. Pull the trim off, remove the reset knob (it unscrews), remove the four screws that hold the lens. Then, remove five screws that attach the digital portion and remove the two slotted screws on either side of the odometer (leave the odometer in the car). Pull the digital section out, it unplugs. When shipping, wrap the dash in aluminum foil, then pack in a large box with packing peanuts.
-John Spina
If your boost lights are not functioning on your digital dash, first pull the connector off the boost indicator switch, with the ignition switch on, short the two wires to ground - the two boost indicators should light up. If they do not - check your bulb.
If they do - the problem is probably your boost indicator switch.
The Boost indicator switch has two contacts. From the factory the low pressure contact is set to 2.5" Hg (1.2 psi), the high pressure contact is set to 10" Hg (4.9psi). If the switch is out of adjustment or you don't like the factory settings you can adjust the set points via the screws onthe back of the boost indicator switch.
I think the boost switches are discontinued from GM.
My digital dash yellow and red idiot boost lights aren't working anymore! I'm still getting boost according to my pillar mounted boost gauge. I know it's just trivial, but how do I fix them?
