The are set to come on at certain boost levels according to their adjustments on the hobbs switch that they are tied to (over on the passenger side inner fender in place of the regular MAP sensor).
Usually they are set to come on at 3# (orange light) and about 6# (red light)
ok. the bottom one has never lit up in the 7 years i have owned the car, and the top one hasnt lit up in a while , and when it did light up it was very rarely.
Could be the switch itself or maybe the vacuum line going to it might be old. Could also be the switch is set too high and you're only occasionally building enough boost to trip the light. They are adjustable.
The bottom bulb should come on first, so maybe it's burned out, or it's connection at the hobbs switch is bad. Maybe the connector needs attention. Look for corrosion.
The bottom bulb should come on first, so maybe it's burned out, or it's connection at the hobbs switch is bad. Maybe the connector needs attention. Look for corrosion.