1996 Bronco/F-Series

Section 15-00: Audio Systems, Service

1996 F-150, F-250, F-350, F-Super Duty and Bronco Workshop Manual

DIAGNOSIS AND TESTING

Pinpoint Tests — Sound System Quality

PINPOINT TEST H: NOISY RECEPTION, AM AND FM

H1 CHECK ANTENNA CABLE CONNECTIONS

Verify condition by operating radio chassis while engine is running, with vehicle in, or not in, motion.
Check antenna connections including extension cable (if equipped).

Are connections clean and secure?

Yes	No
GO to H2.	CLEAN and/or SECURE antenna cable connections as required.

H2 CHECK ANTENNA MOUNTING

Check to make sure antenna is securely mounted to body at ground points.

Are contacts clean and do they have metal-to-metal contact?

Yes	No
GO to H3.	CLEAN and/or SECURE connections as required.

H3 CHECK SUPPRESSION EQUIPMENT

Check for presence of all required suppression equipment, radio frequency interference suppression bond and radio receiver hood bonding strap (if equipped) for security, cleanliness and metal-to-metal connection.

Are connections OK?

Yes	No
GO to H4.	REPLACE missing radio frequency interference suppression bonds, related equipment and/or CLEAN connections as required.

H4 CHECK MOUNTING AND CONNECTING WIRES OF THE FOLLOWING COMPONENTS

NOTE: The capacitor mounting points are used to complete the electrical circuit and must be mounted securely to clean surfaces.

Check the mounting and connecting wires of the generator's radio voltage regulator capacitor (if equipped) and radio ignition interference capacitor for secureness, cleanliness and metal-to-metal contact. Refer to Group 14.

Are connections OK?

Yes	No
GO to H5.	CLEAN and/or SECURE connections as required.

H5 CHECK OPERATION OF THE FOLLOWING COMPONENTS

Check the operation of the generator's radio voltage regulator capacitor and radio ignition interference capacitor by replacing with known good components.
Check generator by disconnecting wiring harness from voltage regulator. Refer to Section 14-02A or Section 14-02B.
Verify radio reception.

Is noise eliminated?

Yes	No
SERVICE or REPLACE damaged components as required.	GO to H6.

H6 CHECK IGNITION WIRES

Check ignition wires for proper routing, grounding and secureness of connections.

Are wires OK?

Yes	No
GO to H7.	REROUTE or REPLACE ignition wires or SECURE connections as required.

H7 CHECK IGNITION SYSTEM

Check ignition system for proper operation. (Use Rotunda Distributorless Ignition System Tester 007-00075 or equivalent or check for open circuit ignition wires using ohmmeter.) Also, check spark plugs for cracked insulators.

Is ignition system OK?

Yes	No
GO to H8.	SERVICE or REPLACE components as required.

H8 CHECK CHASSIS MOUNTING POINTS

Check all radio chassis mounting points for secureness, cleanliness and metal-to-metal contact.

Are mounting points OK?

Yes	No
GO to H9.	CLEAN and/or SECURE as required.

H9 SUBSTITUTE ANTENNA

Substitute a known good radio speaker and antenna, making sure to ground antenna base to an unpainted metal surface.
Verify operation of radio chassis.

Is noise eliminated?

Yes	No
REPLACE or SERVICE radio speaker or antenna.	GO to H10.

H10 SUBSTITUTE ANTENNA EXTENSION CABLE

Substitute a known good radio antenna lead in cable.
Verify operation of radio chassis.

Is noise eliminated?

Yes	No
REPLACE radio antenna lead in cable.	GO to H11.

H11 SUBSTITUTE RADIO

Substitute known good radio chassis.
Verify operation of radio chassis.

Is noise eliminated?

Yes	No
Have radio chassis serviced at an authorized service center.	GO to H12.

H12 CHECK AMPLIFIER

Substitute a known good radio amplifier (premium system only).
Verify operation of radio chassis.

Is noise eliminated?

Yes	No
Have radio amplifier serviced at an authorized service center.	GO to H13.

H13 REPOSITION THE FOLLOWING COMPONENTS

Check if noise can be eliminated by repositioning antenna, radio speaker or radio power feed wires away from other wires and/or brackets.
Verify operation of radio chassis.

Is noise eliminated?

Yes	No
REPOSITION and TAPE in place.	GROUND various parts of the vehicle to the frame using a jumper cable. For example: engine, fenders, quarter panels, stone deflectors, engine air cleaner, body sheet metal. When noise is eliminated, PROVIDE a permanent ground where required.

PINPOINT TEST J: NOISY RECEPTION, AM ONLY

J1 CHECK ANTENNA CABLE CONNECTIONS

Verify condition by operating radio chassis while engine is running, with vehicle in, or not in, motion.
Check antenna cable connections including extension cable (if equipped).

Are connections clean and secure?

Yes	No
GO to J2.	CLEAN and/or SECURE antenna cable connections as required.

J2 CHECK ANTENNA MOUNTING

Check to make sure antenna is securely mounted to body at ground points.

Are contacts clean and do they have metal-to-metal contact?

Yes	No
GO to J3.	CLEAN and/or SECURE connections as required.

J3 CHECK SUPPRESSION EQUIPMENT

Check for presence of all required suppression equipment, radio frequency interference suppression bond and radio receiver hood bonding strap (if equipped) for security, cleanliness and metal-to-metal connection.

Are connections OK?

Yes	No
GO to J4.	REPLACE missing equipment and/or CLEAN connections as required.

J4 CHECK MOUNTING AND CONNECTING WIRES OF FOLLOWING COMPONENTS

Check the mounting and connecting wires of the radio voltage regulator capacitor (if equipped), radio ignition interference capacitor and radio interference capacitor for secureness, cleanliness and metal-to-metal contact. Refer to Group 14.

NOTE: The capacitor mounting points are used to complete the electrical circuit and must be mounted securely to clean surfaces.

Are connections OK?

Yes	No
GO to J5.	CLEAN and/or SECURE connections as required.

J5 CHECK OPERATION OF THE FOLLOWING COMPONENTS

Check the operation of the radio voltage regulator capacitor, radio ignition interference capacitor and radio interference capacitor by replacing with known good components.
Check generator by disconnecting wiring harness from voltage regulator.
Verify radio chassis reception.

Is noise eliminated?

Yes	No
SERVICE or REPLACE damaged components as required.	GO to J6.

J6 CHECK IGNITION WIRES

Check ignition wires for proper routing, grounding and secureness of connections.

Are wires OK?

Yes	No
GO to J7.	REROUTE or REPLACE ignition wires or SECURE connections as required.

J7 CHECK IGNITION SYSTEM

Check ignition system for proper operation. (Use Rotunda Distributorless Ignition System Tester 007-00075 or equivalent or check for open circuit ignition wires using ohmmeter.) Also check spark plugs for cracked insulators.

Is ignition system OK?

Yes	No
GO to J8.	SERVICE or REPLACE components as required.

J8 CHECK CHASSIS MOUNTING POINTS

Check all radio chassis mounting points for secureness, cleanliness and metal-to-metal contact.

Are mounting points OK?

Yes	No
GO to J9.	CLEAN and/or SECURE as required.

J9 SUBSTITUTE ANTENNA

Substitute a known good radio speaker and antenna, making sure to ground antenna base to an unpainted metal surface.
Verify radio chassis operation.

Is noise eliminated?

Yes	No
REPLACE or SERVICE radio speaker or antenna.	GO to J10.

J10 SUBSTITUTE ANTENNA CABLE

Substitute a known good radio antenna lead in cable.
Verify radio chassis operation.

Is noise eliminated?

Yes	No
REPLACE radio antenna lead in cable.	GO to J11.

J11 SUBSTITUTE RADIO

Substitute known good radio chassis.
Verify radio chassis operation.

Is noise eliminated?

Yes	No
Have radio chassis serviced at an authorized service center.	GO to J12.

J12 CHECK AMPLIFIER

Substitute a known good radio amplifier (premium system only).
Verify radio chassis operation.

Is noise eliminated?

Yes	No
Have radio amplifier serviced at an authorized service center.	GO to J13.

J13 REPOSITION THE FOLLOWING COMPONENTS

Check if noise can be eliminated by repositioning antenna, radio speaker or radio power feed wires away from other wires and/or brackets.
Verify operation of radio chassis.

Is noise eliminated?

Yes	No
REPOSITION permanently by taping.	GROUND various parts of the vehicle to the frame using a jumper cable. For example: engine, fenders, quarter panels, stone deflectors, air cleaner, body sheet metal. When noise is eliminated, PROVIDE a permanent ground where required.

PINPOINT TEST K: NOISY RECEPTION, FM ONLY

K1 DETERMINE IF CONCERN IS WITH FM RECEPTION LIMITATION

Verify condition by operating radio chassis with engine running and vehicle not in motion.
If noise is on FM stereo, determine if customer concern is due to FM stereo reception limitation. Refer to Description and Operation.

Is reception normal?

Yes	No
EXPLAIN and DEMONSTRATE to customer. INFORM customer of methods for obtaining best reception.	GO to K2.

K2 CHECK ANTENNA CABLE CONNECTIONS

Check antenna cable connections.

Are connections clean and tight?

Yes	No
GO to K3.	CLEAN and/or SECURE as required.

K3 CHECK ANTENNA MOUNTING

Check to make sure antenna is securely mounted to body and base screws are tight.

Are mounting points tight?

Yes	No
GO to K4.	SECURE as required.

K4 CHECK IGNITION WIRES ROUTING

Check ignition wires for proper routing and secureness of connections.

Are wires OK?

Yes	No
GO to K5.	REROUTE and/or SECURE connections as required.

K5 CHECK TYPE OF IGNITION WIRES

Check if ignition wires are suppressor-type and if spark plugs are the correct type.

Are ignition wires and spark plugs correct?

Yes	No
GO to K6.	REPLACE spark plug or ignition wires with the correct type.

K6 CHECK IGNITION SYSTEM

Check ignition system for proper operation. (Use Rotunda Distributorless Ignition System Tester 007-00075 or equivalent or check for open circuit ignition wires using ohmmeter.) Also check spark plugs for cracked insulators.

Is ignition system OK?

Yes	No
GO to K7.	SERVICE or REPLACE components as required.

K7 CHECK RADIO CHASSIS MOUNTING

Check all radio chassis mounting points for secureness, cleanliness and metal-to-metal contact.

Are radio mounting points OK?

Yes	No
GO to K8.	CLEAN and/or SECURE as required.

K8 SUBSTITUTE ANTENNA

Substitute a known good antenna, making sure to ground antenna base to an unpainted metal surface.

NOTE: All surfaces used for grounding must be clean to ensure good electrical contact. Remove any dirt, rust, grease, paint, or other contaminants.

Verify radio chassis operation.

Is noise eliminated?

Yes	No
REPLACE antenna.	GO to K9.

K9 SUBSTITUTE ANTENNA CABLE

Substitute a known good radio antenna lead in cable.
Verify radio chassis operation.

Is noise eliminated?

Yes	No
REPLACE antenna.	GO to K10.

K10 CHECK GENERATOR

Check generator by disconnecting wiring from voltage regulator.
Verify radio chassis operation.

Is noise eliminated?

Yes	No
CHECK generator. REFER to Section 14-00. SERVICE or REPLACE as required.	GO to K11.

K11 SUBSTITUTE RADIO CHASSIS

Substitute a known good radio chassis.
Verify radio chassis operation.

Is noise eliminated?

Yes	No
Have radio chassis serviced by an authorized service center.	GO to K12.

K12 CHECK AMPLIFIER

Substitute a known good radio amplifier (Premium system only).
Verify radio chassis operation.

Is noise eliminated?

Yes	No
Have radio amplifier serviced at an authorized service center.	GO to K13.

K13 REPOSITION THE FOLLOWING COMPONENTS

Check if noise can be eliminated by repositioning antenna, radio speaker or radio power feed wires away from other wires and/or brackets.

NOTE: All surfaces used for grounding must be clean to ensure good electrical contact. Remove any dirt, rust, grease, paint, or other contaminants.

Verify radio chassis operation.

Is noise eliminated?

Yes	No
REPOSITION permanently by taping.	GROUND various parts of the vehicle to the frame using a jumper cable. For example: engine, fenders, quarter panels, stone deflectors, air cleaner, body sheet metal. When noise is eliminated, PROVIDE permanent ground where required.

PINPOINT TEST L: ONE OR MORE SPEAKERS DISTORTED — NOT ALL SPEAKERS

L1 CHECK FOR DISTORTION

Check all radio speakers for distortion.

Are all radio speakers distorted?

Yes	No
GO to M1.	GO to L2.

L2 CHECK FOR RADIO SPEAKER PROBLEMS

Check for loose trim panels, grilles or attachments which might cause rattles in the area of the radio speaker that is considered distorted.
Check for pinched or broken wires at or near the radio chassis or radio speakers considered distorted.
Check for foreign material in radio speaker(s) cone.

Are there any visible radio speaker concerns?

Yes	No
SERVICE as required. If still distorted, GO to L3.	GO to L3.

L3 CONNECT TEST SPEAKER

Connect a test radio speaker to the wiring for each distorted radio speaker.

Does the test radio speaker get distorted?

Yes	No
GO to L4.	REPLACE radio speaker as required.

L4 CHECK CONNECTIONS AND WIRING

Check for shorts between radio speaker connector.
Check radio chassis and ( if equipped) radio amplifier, wiring harness for damage and shorts.

Are any shorts or damage found?

Yes	No
SERVICE as required.	GO to L5 if equipped with radio amplifier. Otherwise, REMOVE radio chassis for service.

L5 CONNECT TEST AMPLIFIER

Connect a test radio amplifier in place of system radio amplifier.
Verify radio amplifier and radio chassis performance.

Does test radio amplifier cause distortion in radio speakers?

Yes	No
REMOVE radio chassis for service.	REMOVE radio amplifier for service.

PINPOINT TEST M: ALL SPEAKERS DISTORTED

M1 CHECK FOR DISTORTION

Check all radio speakers for distortion.

Are all radio speakers distorted?

Yes	No
GO to M2.	GO to L1.

M2 CHECK VOLUME RANGE FOR DISTORTION

Check volume range for distortion.

Is distortion only at high volume?

Yes	No
System OK. STOP test.	GO to M3.

M3 CONNECT TEST RADIO CHASSIS

Connect a test radio chassis in place of system radio chassis.

Is distortion still present?

Yes	No
REMOVE radio amplifier for service.	REMOVE radio chassis for service.

PINPOINT TEST N: NO SOUND FROM ONE OR MORE SPEAKERS — NOT ALL SPEAKERS

N1 CHECK FOR SOUND AT EACH RADIO SPEAKER

Check for sound at each radio speaker.

Are all radio speakers without sound?

Yes	No
GO to P1.	GO to N2.

N2 CHECK CONNECTORS TO RADIO SPEAKERS

Check wiring to inoperative radio speakers from radio chassis and radio amplifier for opens or shorts.

Are all connections and wiring OK?

Yes	No
GO to N3.	CONNECT, REPLACE or SERVICE as required.

N3 CHECK WITH TEST RADIO SPEAKER

Check system with test radio speaker substituted for system inoperative radio speaker.

Does test radio speaker operate?

Yes	No
REPLACE inoperative radio speaker.	GO to N4.

N4 CHECK RADIO CHASSIS AND RADIO AMPLIFIER WIRING

Check wiring between radio chassis and radio amplifier (if equipped) for damage, broken pins in connectors, solder bridges or stray wires that could cause shorts.

Are connections and wiring OK?

Yes	No
GO to N5.	CONNECT, REPLACE or SERVICE as required.

N5 CHECK WITH TEST RADIO

Substitute a test radio chassis for the system radio chassis.

Does test radio chassis provide sound to all radio speakers?

Yes	No
REMOVE radio chassis for service.	REMOVE radio amplifier for service.

PINPOINT TEST P: NO SOUND FROM ALL SPEAKERS

P1 CHECK FOR SOUND AT EACH RADIO SPEAKER

Key to RUN or ACCESSORY.
Check for sound at each radio speaker.

Are all radio speakers without sound?

Yes	No
GO to P2.	GO to N1.

P2 CHECK POWER OF SYSTEM

Verify power ON and all radio speaker, radio chassis and radio amplifier connections and wiring are not damaged, loose, open or shorting.
With digital volt-ohmmeter, verify power from radio chassis connector C1 Circuit 137 (Y/BK) to ground with key to RUN or ACCESSORY.

Does digital volt-ohmmeter indicate 10 or more volts?

Yes	No
GO to P4.	GO to P3.

P3 CHECK CONTINUITY OF POWER CIRCUITS

Key off.
Using proper schematic for system inoperative, verify continuity of power circuits to source.
Verify voltage at ignition switch with key to RUN (engine off) or ACCESSORY.

Are the power circuits operating?

Yes	No
GO to P4.	SERVICE or REPLACE as required. REFER to Section 14-00.

P4 CHECK FOR SHORT TO GROUND AT SPEAKER(S)

Check for short to ground at one or more radio speakers that can cause radio amplifier shut-down.

Are any shorts found?

Yes	No
REPAIR as required.	REMOVE radio amplifier for service if equipped. Otherwise, REMOVE radio chassis for service.

PINPOINT TEST Q: POOR SOUND QUALITY FROM ONE OR MORE SPEAKERS — NOT ALL SPEAKERS

Q1 CHECK POOR SOUND QUALITY IN RADIO SPEAKERS

Verify poor sound quality in radio speakers.

Is poor sound quality in all radio speakers?

Yes	No
GO to R1.	GO to Q2.

Q2 CHECK RESISTANCE OF RADIO SPEAKER(S)

With power off, check resistance of radio speakers that have poor quality sound from radio amplifier or radio chassis output, back to the return input on radio amplifier or radio chassis.

Is resistance load in excess of the 7 ohm speaker?

Yes	No
CHECK for load in radio speakers or wiring. Excess wire may cause loading effect. REPAIR and RETEST for quality sound.	GO to Q3.

Q3 CHECK RADIO SPEAKER(S)

Check radio speakers for damage to cone or a foreign material causing poor sound.
Verify radio speakers are securely mounted.

Are radio speakers OK?

Yes	No
GO to Q4.	REPAIR or REPLACE radio speakers and RETEST for quality sound.

Q4 CHECK CONNECTIONS AND WIRING

Check connections and wiring at radio speakers, radio amplifier and radio chassis for damage, corrosion or shorts to grounds or loads.

Are connections and wiring OK?

Yes	No
GO to Q5.	REPAIR or REPLACE connections and wiring as required. RETEST for quality sound.

Q5 CHECK WITH TEST RADIO SPEAKER

Substitute a test radio speaker for system radio speakers that have poor quality sound.

Does test radio speaker have poor quality sound?

Yes	No
REMOVE radio chassis for service.	REPLACE or REPAIR radio speakers as required. RETEST for quality sound.

PINPOINT TEST R: POOR SOUND QUALITY FROM ALL SPEAKERS

R1 CHECK POOR SOUND QUALITY IN RADIO SPEAKERS

Verify poor sound quality in radio speakers.

Is poor sound quality in all radio speakers?

Yes	No
GO to R2.	GO to Q1.

R2 CHECK CONNECTIONS AND WIRING

Check connection and wiring at radio speakers, radio amplifier and radio chassis for damage, corrosion or shorts to ground or loads.

Are connections and wiring OK?

Yes	No
GO to R3 if equipped with external radio amplifier. Otherwise, REMOVE radio chassis for service.	REPAIR or REPLACE connections and wiring as required. RETEST for quality sound.

R3 CHECK WITH TEST RADIO AMPLIFIER

Substitute a test radio amplifier for system radio amplifier.

Does test radio amplifier perform with poor quality sound?

Yes	No
REMOVE system radio chassis for service.	REMOVE system radio amplifier for service.