Test Antenna; Generator Whine Concerns - Hummer H1 Service Manual

12-146 Electrical System

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 en-
gine.
• Make sure grounds at starter and intake manifold are
clean and tight.
• Try the following:
1. If noise is still present, check the charging system.
2. If the charging system is functioning normally, check for
technical service bulletins on generator whine.
3. Install a filter P/N 05744279 in the battery feed to the
radio.
4. Try installing the filter with the following variations if the
noise is not eliminated.
a. Install the filter with the single wire side toward the
radio and the ground wire attached to a good ground.
b. Remove the ground to the filter.
c. Reverse the filter so the two wire side is toward the
radio with the ground wire attached to a good ground.
d. Remove the ground from the filter.
5. 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.
6. Remove any unneeded filters after repair, before
reassembling the vehicle.
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