Typical Entertainment System Troubleshooting Tips
GENERAL INFORMATION^ Before troubleshooting a car, check for the presence and proper installation of all suppression components (capacitors and ground straps).
^ When substituting components (EG. Electronic cluster and ignition system), the cause is probably in the radio system (defective radio or antenna cable).
TAPE NOISE SYMPTOM
^ Purr varying with engine RPM most noticeable at minimum volume
^ Unique to cassette radio in F-Series and Bronco
SOURCE: Power feed (37 ckt) wire routed in close proximity to the radio chassis.
CAUSE CORRECTIVE ACTION
Magnetic Coupling to Tape Re-route 37 cht wiring per TSB
pre-amplifier circuitry 83-7-17 procedure on customer
concern basis
AM/FM NOISE SYMPTOM
^ Buzz, purr or whine varying with engine RPM, most noticeable at minimum volume with premium sound on
SOURCE: Ignition and/or charging system
POTENTIAL CAUSE CORRECTIVE ACTION
Ground cable on premium Check for proper installation of
sound amplifier missing or im- ground cable between amplifier
propely installed and rear stud of radio (on carlines
equipped with ground cables)
Improper attachment of cables Check attachment of battery
cables at posts and battery ground cable at engine block. Check attachment of other ground cables. Clean terminals and mounting surfaces. Torque attaching hardware to specification.
Radio A-line fittering defective Power radio directly from separate
battery. If noise is not present, replace radio.
Low battery charge condition Charge or replace as required.
FM NOISE SYMPTOM
^ Buzzing or tone usually at discrete dial locations
^ Engine Off
^ Ignition switch in run or accessory position
^ All motorized equipment turned off
^ Noise minimized when antenna is disconnected from radio
SOURCE: Electronic Module
POTENTIAL CAUSE CORRECTIVE ACTION
Module radiating in band with Remove fuses one-by-one from
sufficient energy to be de- the fuse panel until the offend-
tected by the radio ing power feed buss is identified
Consult the troubleshooting manual and identify modules fed from the offending power buss Disconnect these modules one at a time until the noisy unit is isolated Install substitute module If noise occurs with key in the run position but not in the accessory position then check the electronic engine control module by disconnecting it from vehicle wiring.
NOTE: The ignition key should be in the off position when disconnecting or reconnecting EEC module
Defective Antenna Perform antenna check. Replace
antenna cable is defective
AM NOISE SYMPTOM
^ Hash or whine heard only with WSW, blower or cooling fan motor on.
SOURCE: WSW, blower or cooling fan motor
POTENTIAL CAUSE CORRECTIVE ACTION
Antenna system defective Perform antenna system check.
Replace antenna cable if required.
AM NOISE SYMPTOM
^ Variable frequency oscillation or hash that is heard with engine off
SOURCE: Electronic instrumentation or module
POTENTIAL CAUSE CORRECTIVE ACTION
Antenna system defective Perform antenna system check.
Replace antenna cable if required.
Defective electronic instru- Remove fuses one-by-one from
mentation fuse panel, until the offending
power feed buss is identified Consult the troubleshooting manual and identify modules fed from the offending power buss Disconnect these modules one-byone until the noisy unit is isolated Install substitute module
AM NOISE SYMPTOM
^ Popping noise that varies with engine speed
^ Not present with engine off
^ Does not vary with addition of electrical loads (headlight, rear defroster)
^ Not present at minimum volume
SOURCE: Ignition system
POTENTIAL CAUSE CORRECTIVE ACTION
Antenna system defective Perform antenna system check.
Replace antenna cable if required.
Loose spark plug or coil wire Seat all spark plug and coil wires
Radio A-line filtering defective Power radio directly from separate
battery. If noise is not present, replace radio.
Improper cable attachments Check attachment of battery
cables at posts and battery around cable at engine block. Check attachment of other ground cables. Clean terminals and mounting surfaces. Torque attaching hardware to specification.
AM NOISE SYMPTOM
^ A whine that varies with engine RPM and electrical loads. Noise not heard with engine off or voltage regulator disconnected.
SOURCE: Charging System
POTENTIAL CAUSE CORRECTIVE ACTION
Antenna system defective Perform antenna system check.
Replace antenna cable if required.
Radio A-line filtering defective Power radio directly from separate
battery. If noise is not present, replace radio.
Defective voltage regulator Replace voltage regulator capa-
capacitor citor, if vehicle is equipped with
one.
Defective Voltage Regulator Replace voltage regulator
Defective alternator Replace alternator
Low battery charge condition Charge or replace as required.
OTHER APPLICABLE ARTICLES: None
WARRANTY STATUS: "INFORMATION ONLY