Hummer H1 (2006+). Manual — part 225

6-50

Wheels and Tires/Central Tire Inflation System (CTIS)

_______________

AIR PRESSURE GAUGE

WARNING: The CTIS components are subject to high air pressure. Always relieve the air pressure before loosen-
ing or removing air system components by disconnecting quick-disconnect valve assemblies. Failure to follow this
warning may result in serious injury.

Removal

1.

Remove the CTIS module from the instrument panel.

2.

Remove the lamp from the air pressure gauge (Figure 6-54).

3.

Disconnect the two air pressure indicator lines from the air pressure gauge.

4.

Remove the two nuts, lock washers, bracket and air pressure gauge from the CTIS module (Figure 6-54). Discard lock
washers.

Cleaning and Inspection

Clean and inspect the air pressure gauge and lamp. Check for cracks and stripped threads. Replace the defective parts.

CAUTION: Do not allow sealant into the air system. Sealant will damage CTIS components.

NOTE: Apply sealant to the threads prior to installation.

Installation

1.

Install the air pressure gauge and bracket on the CTIS module with two nuts and lock washers. Tighten the nuts to 8 lb-in. (0.9
N•m)(Figure 6-54).

2.

Connect the air pressure indicator lines in the original position.

3.

Install the lamp in air pressure gauge.

4.

Install the CTIS module in the instrument panel.

5.

Start the engine and ensure the air pressure gauge operates properly.

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Wheels and Tires/Central Tire Inflation System (CTIS) 6-51

5745804

Figure 6-54: Air Pressure Gauge Replacement

AIR PRESSURE GAUGE BULB REPLACEMENT

Air Pressure Gauge Back Lighting

The air pressure gauge back lighting is the only lighting component that is serviceable on the CTIS control unit. To service the bulb
in the air pressure gauge, pull the harness and bulb socket out of the back of the air pressure gauge. With the harness and bulb
socket removed from the air pressure gauge, twist the bulb a quarter of a turn from the harness receiver and remove the bulb.

AIR PRESSURE

GAUGE

PRESSURE

GAUGE LAMP

6-52

Wheels and Tires/Central Tire Inflation System (CTIS)

_______________

Figure 6-55: Air Pressure Gauge Lamp Replacement

CTIS LOW PRESSURE ALARM REPLACEMENT

Removal

1.

Remove the interior fuse box access panel in the left close out panel under the instrument panel.

2.

Remove the low pressure alarm from the face of the interior fuse box(Figure 6-56).

Installation

1.

Install the low pressure alarm on the interior fuse box.

2.

Install the fuse box access panel in the left closeout panel.

AIR PRESSURE

GAUGE BULB

BULB

SOCKET

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Wheels and Tires/Central Tire Inflation System (CTIS) 6-53

5745804

Figure 6-56: Low Pressure Alarm Location

CTIS INTERIOR HARNESS

NOTE: Prior to removal, tag all the leads for installation.

Removal

1.

Remove the CTIS module from the instrument panel and gain access to the back.

2.

Disconnect the harness connector from the inflate/deflate and tire selector switches (Figure 6-57).

3.

Remove the lamp from the air pressure gauge.

4.

Disconnect the harness connector from the I/P harness connector and remove the CTIS interior harness.

Cleaning and Inspection

Clean and inspect the CTIS harness and connectors. Check for defects such as frayed wires and cracks. Repair or replace the defec-
tive parts.

Installation

1.

Connect the CTIS harness connector to the I/P harness connector (Figure 6-57).

2.

Install the lamp in the air pressure gauge.

3.

Connect the CTIS harness to the inflate/deflate and tire selector switches.

4.

Install the CTIS module in the instrument panel.

LOW

PRESSURE

ALARM

INTERIOR

FUSE

BOX

9-S06-011