System Diagnosis - Analog Cluster

BUICK & CADILLAC
Operation
This system consists of green and amber indicator lights located on the fuel gauge or telltale lamp cluster, a switch mounted on the instrument panel behind the gauges and an interconnecting vacuum hose and tee. The system operates on engine vacuum through a dual contact vacuum sensing switch. When the accelerator is operated slowly and smoothly, engine vacuum remains high and the switch passes current to the green indicator light which indicates economical fuel consumption. When the accelerator pedal is depressed rapidly, vacuum decreases and the switch passes current to the amber indicator light, which indicates high fuel consumption. The amber indicator light will glow when the ignition switch is in the ``On'' position with the engine stopped.
Functional Test
1. With ignition switch in the on position, ground each terminal at the economy switch. Both green and amber indicator lights should glow. If not check for burned out bulbs.
2. With ignition switch in on position, amber indicator light should glow. If not, check for loose or disconnected wires at fuel economy switch or for poor ground. If amber indicator light still does not glow replace switch.
3. Start engine and allow to idle, the green indicator light should glow. If not, check for leaking, plugged or kinked vacuum hose between vacuum source and fuel economy switch. Check for loose or disconnected wires at economy switch or poor ground. If green indicator lamp still does not glow, replace switch.