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Hummer H1 (2006+). Manual - part 360

12-116

Electrical System

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Figure 12-80: Audio Harness Connections.

DIAGNOSIS -AUDIO SYSTEM

Verify the customer complaint.

Follow the radio service procedures.

If any technical service is required, have all the pertinent information ready before placing the call.

NOTE: Before performing any diagnostic procedures or using any diagnostic tools, check wiring schematics for component cir-
cuitry to determine the location of fuses and circuit breakers in the circuit. Fuses and circuit breakers must be in good working or-
der to perform proper diagnostic procedures.

Audio System Diagnostic Kit J–39916-A is available from Kent-Moore. The kit contains a diagnostic CD and cassette, a head
cleaner cassette and instructions. This kit is designed to isolate the type of malady and the area of its origin by producing tones of
various frequencies. By adjusting the fade and balance, a technician can evaluate the sound quality produced in different areas of
the system.

Identifying Concerns

• Check for technical service bulletins.

• For reception concerns, determine if the station is obtainable in the customers listening area.

• To test for audio reception/noise, position the vehicle outside the building with the hood down.

• Duplicate the customers complaint before trying to diagnose the system. Have the customer demonstrate the condition. Test

drive the vehicle with the customer and then test drive another similar model vehicle (with a similar audio system) to do a
comparison of the two vehicles to determine if the condition is abnormal.

• Before diagnosing, identify components, their features and the customer’s complaint.

• Determine if any aftermarket equipment is installed on the vehicle. Disconnect the aftermarket equipment and determine if

the customers complaint still exists.

• Perform the following steps to identify a noisy component:

Identify the ignition switch key position in which the noise appears, such as: accessory, key on engine not running, and key on
engine running.

Remove the fuses one at a time until the complaint condition has been eliminated.

Mark the complaint fuse(s) and reinstall all the fuses and circuit breakers.

Identify all the systems and the components powered by the complaint fuse(s).

Disconnect the components powered by the complaint fuse(s) one at a time until the complaint condition has been eliminated
and the noisy component has been identified.

AUDIO

ANTENNA LEAD-IN

HARNESS

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Electrical System 12-117

Check the ground integrity of the complaint causing component.

• An interference condition is not necessarily an audible noise.

• Most noises can be found on weak stations near the low end of the band and are considered to be a normal condition.

• Malfunctioning and marginal components, relays, and solenoids may induce noise and/or poor reception.

Check for a broken (or partially broken) wire inside of the insulation which could cause system malfunction but prove “good”
in a continuity/voltage check with a system disconnected. These circuits may be intermittent or resistive when loaded, and if
possible, should be checked by monitoring for a voltage drop with the system operational (under load).

Corrective Action

• Use proper tools for diagnostics and repairs.

• Follow electrical system diagnostic guidelines.

• Use available noise suppression devices:

—Filter package P/N 05744279

Utilize the test tape /CD Diagnostic Kit Kent-Moore
P/N J–39916-A to optimize proper audio diagnostics.

• If the condition requires the radio to be sent to the service center, describe the symptoms on the warranty form exactly.

• Do not leave a CD disc or tape in the vehicle. Extreme heat could cause permanent damage.

• Cassette tapes could be damaged if not stored in the case. The vibration in the vehicle can cause the tape to unwind inside

the cartridge.

• Use available trouble trees.

• Before removing speaker(s), check all connectors and wiring to the speakers. Examine the connectors for bent or loose pins.

Refer to troubleshooting procedures.

• If a test antenna is used in diagnostics, ground the antenna base to the vehicle body and do not hold the mast.

NOTE: Check the antenna coax connectors for corrosion or bad connections/crimps. Route coax separately from the other wires.
Shield antenna coax interconnections with aluminum or nickel tape. Check all vehicle grounds, not just antenna and radio grounds.
Refer to the antenna diagnostic section.

• Coated screws or bolts can act as poor grounds.

• Always use a braided ground strap when applying grounds. Keep the ground strap as short as possible, the shorter the

ground strap the better.

• When shielding the dash, wires, hoses (most hoses are conductive unless they have a white stripe), use aluminum foil tape or

nickel tape to shield against magnetically induced interference. For optimum performance try varying the following ground
techniques:

—Add a ground at both ends of the tape.

—Add a ground to just one end of the tape.

—Do not add ground to the tape.

• When shielding a harness with tape, attach a ground strap to the end of the tape and then wrap the strap 360 degrees around

the tape securing the other end of the strap to a known good chassis ground.

• Any interference is best corrected by suppression at the source of the interference, if possible.

• Care should be used when applying suppression. Signal wires (such as sensor outputs, clock, and communication circuits)

cannot be suppressed. After adding any suppression, all vehicle systems (even those not related to the audio system) should
be checked for proper operation and function.

• Interference can usually be eliminated by shielding/grounding or suppressing.

• Capacitors work best on switch pops and low frequency noise. Filters work best on high frequency whines and static.

• Whenever possible, make a test harness that includes filters and capacitors. Always check the effectiveness and operation

before permanently installing a fix.

12-118

Electrical System

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• Recommended capacitor application for an audible pop induced from a switching operation is:

—Add a capacitor across the contacts of the switch.

—Add a capacitor from the hot side of the switch to ground.

—Add a capacitor to each side of the switch to ground.

• If a complaint condition is only present with the ignition key in the run position and the engine running, perform the follow-

ing checks:

—Check the integrity of the engine compartment grounds.

—Check for malfunctioning relays, solenoids, or other components which may be inducing “noise” or poor reception.

—Check the ground integrity of the complaint causing component.

• For noise and/or poor reception, perform the antenna system test and make the necessary repairs.

TEST ANTENNA

The test antenna is simply an antenna that is not mounted on the vehicle. This tool is used as a substitute for the antenna mounted
on the vehicle. The technician should connect the test antenna to the antenna input of the radio. Ground the base of the antenna to
the vehicle’s chassis. Do not hold the mast of the antenna. This will decrease the capability of the antenna to receive a station.

GENERATOR WHINE CONCERNS

• Check the ground terminal on the battery.

• Check for coated mounting bolts on the generator bracket.

• Check for a faulty mounting of the generator to the engine.

• Make sure grounds at starter and intake manifold are clean and tight.

• Try the following:

If a noise is still present, check the charging system.

If the charging system is functioning normally, check for technical service bulletins on generator whine.

Install a filter P/N 05744279 in the battery feed to the radio.

Try installing the filter with the following variations if the noise is not eliminated.

Install the filter with the single wire side toward the radio and the ground wire attached to a good ground.

Remove the ground to the filter.

Reverse the filter so the two wire side is toward the radio with the ground wire attached to a good ground.

Remove the ground from the filter.

If the noise is still present, install another filter P/N 05744279 in the ignition feed to the radio. Install using the same variations
as the first filter. If the installation of this filter causes turn on or turn off delays or other noticeable performance concerns,
remove it and install a 0.47 mf (microfarad) capacitor in its place.

Remove any unneeded filters after repair, before reassembling the vehicle.

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Electrical System 12-119

Symptom Table

DISPLAY IS INOPERATIVE, NO SOUND FROM ANY SPEAKER

SYMPTOM

PROCEDURE

PAGE NUMBER

Display inoperative, no sound from any
speaker.

Chart #1

12-119

No sound from one speaker (std.).

Chart #2

12-120

No sound from one speaker (Monsoon).

Chart #3

12-120

No sound from any speaker, radio dis-
play operates normally (Monsoon).

Chart #4

12-122

Antenna system test.

Chart #5

12-123

Rear seat audio does not operate.

Chart #6

12-123

Radio controls are inoperative.

Service radio.

Radio does not turn off.

Service radio.

Radio memory (clock and station pre-
sets) is inoperative.

Check ckt. 476 for an open or high
resistance between radio connector ter-
minal “7” and fuse 2H.

Display dimming does not vary using
the I/P dimmer switch (I/P dimming
works).

Check ckt. 17 for an open or high resis-
tance between radio connector terminal
“6” and the panel light dimmer.

Speaker output distorted at high volume
(Monsoon).

Check for open or poor connection in
ckt. 59 from amplifier terminals “E8”
and “E9” to the I/P ground point. Check
for open or poor connection in ckt. 829
from amplifier terminals “E11” and
“E12” to fuse 1D.
If OK, replace amplifier.

CHART #1

STEP

ACTION

VALUE(S)

YES

Disconnect radio connector.

Ignition switch to “run”.

With a DVOM, measure voltage between
terminal B1 and ground.

Approxi-
mate bat-
tery
voltage.

Go to step 2.

Repair poor connection or

open in ckt. 476 between

radio connector terminal

B1 and fuse 2H.

With a DVOM, measure voltage
at radio connector between termi-
nal B1 and
terminal A12.

Approxi-
mate bat-
tery
voltage.

Go to step 3.

Repair poor connection or

open in ckt. 59 between

radio connector terminal

A12 and ground point G4.

With a DVOM, measure voltage
at radio connector between termi-
nal B2 and
terminal A12.

Approxi-
mate bat-
tery
voltage.

Go to step 4.

Repair open in ckt. 137

between radio connector

terminal B2 and fuse 4G.

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