Mark VII V8-302 5.0L VIN F FI (1987)
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Note the reception performance of a known good vehicle in the desired locations. Note the presence of any local external noise sources (eg. power
lines, etc.).
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Compare the performance of the concern vehicle when receiving the test stations in the same locations.
FM Signal Issue - Diagnostic Tips:
B.
FM Signal Issue - Diagnostic Tips:
Educational/Public radio stations typically make the best test signals when you are looking for weak FM stations. They are often low power stations.
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These stations are generally at the low end of the FM broadcast band.
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They will often carry classical music, or other programs with many "quiet" passages. It is during the quiet passages that noise from the vehicle is
most noticeable.
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It is best to choose two or three of these weak stations and use them each time you perform a test, in order to become accustomed to how these
stations sound in "good" cars and what external interference noise is normal.
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This should be done with the engine both running and not running.
If the customer has a concern about a particular station, be sure to test the radio on that station too. Keep in mind that the noise may only be heard in one
part of the band, just as a radio station is only heard on one frequency.
Summary:
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Select a set of test stations (2 to 3 weak stations or stations that are a customer concern), typically at the low end of the FM band.
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Note the reception performance of a known good vehicle in the desired locations. Note the presence of any local external noise sources (eg. power
lines, etc.).
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Compare the performance of the concern vehicle when listening to the test stations in the same locations.
Diagnosing AM Band Alternator Wine and Ignition Noise
C.
Diagnosing AM Band Alternator Whine:
Alternator noise is heard as a smooth, high pitched "whine" (as opposed to a low pitched, rough "tick" of ignition noise). The pitch of the whine will vary
with engine RPM. The volume of the whine may also vary with changes in the electrical load (eg. headlamps and heated backlight).
D.
Diagnosing AM Band Ignition Noise:
Ignition noise is heard as a sharp or rough "tick" (as opposed to the higher pitched smooth whine of alternator noise). The frequency of the "tick" varies
with RPM.
Static & Weak Reception Town Car AM
E.
Lincoln Town Car:
Excessive AM static on strong stations, poor reception, fading under bridges and overpasses.
To service this concern, the original antenna cable is disabled and the new antenna cable is installed and rerouted down the center of the vehicle . Also, a
radio to instrument panel ground strap is installed. Use the following instructions to service this concern.
DISABLE ORIGINAL ANTENNA
1.
Remove radio. Refer to the 1990-91 Lincoln Town Car Service Manual, Section 35-01.
2.
Disconnect antenna cable from power antenna and radio.
NOTE:
CUT OFF THE ENDS OF THE ANTENNA CABLE SO THERE IS NO CHANCE THAT IT WILL BE USED AGAIN. SECURE THE CABLE
ENDS AFTER CUTTING TO PREVENT RATTLES.
