Symptom Chart

WARNING: This page is about a different car, the 2006 Mercury Mariner and 2006 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

SYMPTOM CHART

Condition	Possible Sources	Action
The audio unit display is blank, but the audio unit operates	Audio unit	REMOVE the audio unit. REFER to AUDIO UNIT in this article. SEND it to an authorized audio system repair facility. TEST the system for normal operation after the repair.
During CD mode, the audio unit display shows: NO CD	No CD found	INSERT a known good CD. If the concern is still present, REMOVE the audio unit. REFER to AUDIO UNIT in this article. SEND it to an authorized audio system repair facility. TEST the system for normal operation after the repair. Otherwise, NOTIFY the customer of the faulty CD.
One or more audio control buttons (such as volume, seek, tune, and scan) is inoperative in either radio, tape, or all modes, but the audio unit display functions correctly	Audio unit	REMOVE the audio unit. REFER to AUDIO UNIT in this article. SEND it to an authorized audio system repair facility. TEST the system for normal operation after the repair.
When the headlamp switch is in the PARK or ON position, there is no front audio unit backlighting, but all other backlighting functions are normal	Circuitry Audio unit	REFER to INSTRUMENT CLUSTER AND PANEL ILLUMINATION to continue diagnosis of the backlighting system.
The audio unit is inoperative/does not operate correctly	Fuse(s) Circuitry Audio unit	GO to PINPOINT TEST A .
The audio unit does not operate correctly - speed sensitive volume	Circuitry Audio unit	GO to PINPOINT TEST F .
Poor reception	Antenna Antenna cable(s) Antenna connections Noise suppression equipment Audio unit	GO to PINPOINT TEST B .
Continuous SEEK/SCAN in AM/FM	Antenna Antenna cable(s) Antenna connections Noise suppression equipment Audio unit	GO to PINPOINT TEST B .
No sound from all speakers	Fuse(s) Circuitry Audio unit	GO to PINPOINT TEST A .
No sound from one or more of the speakers (not all speakers)	Speaker(s) Circuitry Audio unit	GO to PINPOINT TEST C .
Poor quality/distorted sound from one or more speakers (not all speakers)	Speaker(s) Circuitry Audio unit	GO to PINPOINT TEST C .
Poor quality/distorted sound from all speakers	Audio unit	If the condition only occurs when the vehicle is running, GO to PINPOINT TEST B . Otherwise, REMOVE the audio unit. REFER to AUDIO UNIT in this article. SEND it to an authorized audio system repair facility. TEST the system for normal operation after the repair.
The subwoofer is inoperative	Fuse Circuitry Subwoofer/amplifier Audio unit	GO to PINPOINT TEST D .
Loud popping sound when cycling the ignition	Circuitry Subwoofer amplifier Audio unit	GO to PINPOINT TEST E .