Series 638 – Section 2.8 Coolant Temperature Switch (Dash Light)

Section 2.8
Coolant Temperature Switch (Dash Light)

The purpose of the coolant temperature switch is to activate a dashboard mounted light to warn the user that the engine is not operating within normal operating parameters.‪

Section 2.8.1
Replacement of Coolant Temperature Switch (Dash Light)

To determine if replacement of the coolant temperature sensor (dash light) is necessary, perform the following procedure. See Figure "Flowchart for Replacement of Coolant Temperature Sensor (Dash Light)" .‪

Note: The CTS is non-serviceable and should be replaced as necessary.

Figure 1. Flowchart for Replacement of Coolant Temperature Sensor (Dash Light)

Section 2.8.2
Removal of Coolant Temperature Switch (Dash Light)

Remove the coolant temperature switch as follows:‪

1. Drain the cooling system. Refer to "13.4.5 Cooling System" .
2. Disconnect the coolant temperature switch wire harness. See Figure "Coolant Temperature Switch and Wire Harness Removal" .
   

   1.Number 6 Cylinder Head‪

   2.Coolant Temperature Switch‪

   Figure 2. Coolant Temperature Switch and Wire Harness Removal

3. Remove the coolant temperature switch. See Figure "Coolant Temperature Switch and Wire Harness Removal" .

Section 2.8.2.1
Inspection of Coolant Temperature Switch (Dash Light)

Inspect the coolant temperature switch as follows:‪

1. Visually check the coolant temperature switch for corrosion or rust.
   1. If the coolant temperature switch has corrosion or rust, clean as necessary. Refer to "2.8.3 Installation of Coolant Temperature Switch (Dash Light)" .
   2. If the coolant temperature switch has no corrosion or rust, proceed with step 2 of inspection.
2. Visually check the coolant temperature switch for bent, broken, or missing pins.
   1. If the coolant temperature switch has bent, broken, or missing pins, replace the component. Refer to "2.8.3 Installation of Coolant Temperature Switch (Dash Light)" .
   2. If the coolant temperature switch has no bent, broken, or missing pins, reuse the component. Refer to "2.8.3 Installation of Coolant Temperature Switch (Dash Light)" .

Section 2.8.3
Installation of Coolant Temperature Switch (Dash Light)

Install the coolant temperature switch as follows:‪

1. Install the coolant temperature switch. See Figure "Coolant Temperature Switch and Wire Harness Removal" .
2. Reconnect the coolant temperature switch.
3. Fill the cooling system. Refer to "13.4.5 Cooling System" .
4. Run the engine to verify repair.