For 1990-2009 cars

### Purpose

The oil pressure switch and the coolant level switch are connected to the Powertrain Control Module (PCM). If a low oil pressure condition, or a low coolant level condition is detected, the PCM will send a signal to the Instrument Panel Cluster (IPC). The IPC will receive this signal from the PCM and the IPC will then illuminate the warning lamp.

The electronic instrument cluster uses 2 telltale lamps. A Low Oil Pressure telltale lamp indicates low engine oil pressure. A Low Coolant Level telltale lamp indicates a low coolant level condition. The purpose of these lamps are to warn the operator of potential engine damaging conditions. If any of the warning lamps are illuminated, then a condition is present that may cause engine damage.

### Engine Oil Pressure Indicator Switch

The engine oil pressure indicator switch indicates low engine oil pressure. The oil pressure indicator switch has normally closed contacts that open when oil pressure is greater than 41 kPa (6 psi). The contacts will close when oil pressure is less than 14 kPa (2 psi). When the contacts are closed, the oil pressure signal is sent to the Powertrain Control Module (PCM). The PCM then sends this signal to the Instrument Panel Cluster (IPC) through to illuminate the oil pressure telltale lamp on the IPC.

### Coolant Level Switch

The coolant level switch is an assembly containing a reed switch and magnetic float. When the coolant level is normal, the float rests away from the reed switch, causing the switch to open. When the coolant level is low, the float rests near the reed switch and causes the switch to close.

The coolant level switch is mounted in the radiator surge tank. If the coolant level falls below a specific level, the contacts close, and a signal is sent to the PCM. The PCM will then send this signal to the IPC to illuminate the coolant level telltale lamp.