Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2008 Hummer H3 L5-3.7LFACTORY OEM SERVICE PROCEDURE
Coolant Temperature Sensor/Switch (For Computer): Locations
Right Rear of the Engine Components (LLR)
1 - Manifold Absolute Pressure (MAP) Sensor
2 - Throttle Body
3 - Ignition Coil 3
4 - Ignition Coil 2
5 - Ignition Coil 1
6 - Camshaft Position (CMP) Actuator Solenoid Valve
7 - Engine Oil Pressure (EOP) Switch
8 - Heated Oxygen Sensor (HO2S) 1
9 - Engine Coolant Temperature (ECT) Sensor
10 - Engine Coolant Temperature (ECT) Sensor Connector
11 - X101
12 - Ignition Coil 5
13 - Ignition Coil 4
Engine - Left (LH8)
1 - Engine Coolant Temperature (ECT) Sensor
2 - Generator
3 - Ignition Coil 1
4 - Evaporative Emission (EVAP) Canister Purge Solenoid Valve
5 - Ignition Coil 3
6 - Ignition Coil 5
7 - Ignition Coil 7
8 - Engine Oil Pressure (EOP) Sensor
9 - Park/Neutral Position (PNP) Switch (M30)
10 - Knock Sensor (KS) 1
11 - Engine Block Heater Connector (K05)
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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