Chrysler PT Cruiser, Service & Repair Manual, Page: 304 / 2078

shielding the radio waves as they are conducted to
the radio. The radio then tunes and amplifies the
weak radio signals into stronger electrical signals in
order to operate the audio system speakers.
DIAGNOSIS AND TESTING - ANTENNA BODY
AND CABLE
The following four tests are used to diagnose the
antenna with an ohmmeter:
•
Test 1 - Mast to ground test
•
Test 2 - Tip-of-mast to tip-of-conductor test
•
Test 3 - Body ground to battery ground test
•
Test 4 - Body ground to antenna coaxial cable
shield test.
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, SEAT BELT TENSIONER, SIDE
AIRBAG, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
The ohmmeter test lead connections for each test
are shown in the illustration (Fig. 1).
NOTE: This model has a two-piece antenna coaxial
cable. Tests 2 and 4 must be conducted in two
steps to isolate an antenna cable problem. First,
test the primary antenna cable (integral to the
antenna body and cable) from the coaxial cable
connector under the right end of the instrument
panel near the right cowl side inner panel to the
antenna body. Then, test the secondary antenna
cable (instrument panel antenna cable) from the
coaxial cable connector under the right end of the
instrument panel near the right cowl side inner
panel to the coaxial cable connector at the radio.
TEST 1
Test 1 determines if the antenna mast is insulated
from ground. Proceed as follows:
(1) Disconnect and isolate the antenna coaxial
cable connector under the right end of the instru-
ment panel near the right cowl side inner panel.
(2) Touch one ohmmeter test lead to the tip of the
antenna mast (below tip if ball tip is plastic). Touch
the other test lead to the antenna cap nut. Check the
ohmmeter reading for continuity.
(3) There should be no continuity. If OK, go to Test
2. If not OK, replace the faulty antenna body and
cable.
TEST 2
Test 2 checks the antenna conductor components
for an open circuit. This test should be performed
first on the entire antenna circuit, from the antenna
mast to the center conductor of the coaxial cable con-
nector at the radio. If an open circuit is detected,
each of the three antenna conductor components
(antenna mast, antenna body and primary cable unit,
instrument panel antenna secondary cable) should be
isolated and tested individually to locate the exact
component that is the source of the open circuit. To
begin this test, proceed as follows:
(1) Disconnect the instrument panel (secondary)
antenna cable coaxial connector from the back of the
radio.
(2) Touch one ohmmeter test lead to the tip of the
antenna mast. Touch the other test lead to the center
conductor pin of the instrument panel antenna cable
coaxial connector for the radio. Check the ohmmeter
reading for continuity.
(3) There should be continuity. The ohmmeter
should register only a fraction of an ohm resistance.
High or infinite resistance indicates a damaged or
open antenna conductor. If OK, go to Test 3. If not
OK, isolate and test each of the individual antenna
conductor
components. Replace only the faulty
antenna conductor component.
Fig. 1 Antenna Tests - Typical
8A - 4 AUDIO
PT
ANTENNA BODY & CABLE (Continued)