Low Coolant Sensor - Hummer H1 Service Manual

4-12 Cooling System
SURGE TANK-TO-LOWER RADIATOR TUBE
HOSE REPLACEMENT
Removal
1. Drain cooling system.
2. Loosen clamps and remove hose from surge tank and
lower tube assembly (Figure 4-20).
Installation
1. Install hose on lower tube assembly and surge tank and
tighten clamps (Figure 4-20).
2. Fill cooling system.
LOWER
TUBE ASSEMBLY
SURGE TANK-TO-LOWER TUBE
Figure 4-20: Surge Tank-to-Lower Tube Assembly
Hose Location
__________________________________________________________
SURGE TANK
ASSEMBLY HOSE

LOW COOLANT SENSOR

The coolant level sensor is a solid-state semi-conductor device.
The sensor's resistance varies as a function of its temperature.
As voltage/current flows through the sensor, sensor tempera-
ture increases. In the presence of a liquid, in this case engine
coolant, the temperature of the sensor is controlled by transfer-
ring heat to the coolant. Should the coolant level drop below
the sensor, the heat and resistance of the sensor will rise. The
"Low Coolant" warning light will then illuminate in response
to the increased resistance at the sensor.
Removal
1. Drain and collect coolant from surge tank.
2. Disconnect the low coolant sensor electrical connector
from the engine harness connector.
3. Remove the sensor and O-ring from the surge tank
(Figure 4-21)
O-RING
LOW
COOLANT
SENSOR
Figure 4-21: Low Coolant Sensor
Installation
1. Position O-ring on sensor and thread sensor into surge
tank (Figure 4-21).
2. Plug the low coolant sensor electrical connector into the
engine harness connector
3. Fill surge tank with coolant.
®
ELECTRICAL
CONNECTOR
SURGE
TANK