Left Rear Input No Activity

LEFT REAR INPUT NO ACTIVITY

WHEN MONITORED
When the DRBIII(R) performs the amplifier Input Test.

SET CONDITION
The Amplifier detects no activity on the input circuit.

POSSIBLE CAUSES
- (+) Circuit shorted to ground
- (-) Circuit shorted to ground
- Open speaker circuits
- Radio
- Amplifier

1. (+) CIRCUIT SHORTED TO GROUND

NOTE: The fault condition must be present to continue diagnosis. Use the DRBIII(R) to perform the Amplifier pretest to verify the fault condition is present before continuing diagnosis.

Turn the ignition off.
Disconnect the Amplifier C1 harness connector.
Disconnect the Radio harness connector.
Measure the resistance between ground and the left rear speaker (+) circuit.

Q: Is the resistance below 1000.0 (1K) ohms?

YES: Repair the speaker (+) circuit for a short to ground. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 2

2. (-) CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Disconnect the Amplifier C1 harness connector.
Disconnect the Radio harness connector.
Measure the resistance between ground and the left rear speaker (-) circuit.

Q: Is the resistance below 1000.0 (1K) ohms?

YES: Repair the speaker (-) circuit for a short to ground. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 3

3. OPEN SPEAKER CIRCUITS
Turn the ignition off.
Disconnect the Amplifier C1 harness connector.
Disconnect the Radio harness connector.
Measure the resistance of each left rear speaker (+) and (-) circuit between the Radio and the Amplifier.

Q: Is the resistance below 5.0 ohms for each circuit?

YES: Go To 4
NO: Repair the speaker circuits for an open. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

4. AMPLIFIER
Turn the ignition off.
Reconnect the Radio harness connector.
Disconnect the Amplifier C1 harness connector.
Turn the ignition on and the Radio on to a known good radio station or have a tape or CD playing.
Turn the radio volume control up at least 25 positions.
With the voltmeter in the AC voltage scale, measure the voltage of each left rear speaker circuit at the Amplifier C1 connector.

NOTE: Perform this test on each left rear speaker circuit.

Q: Is the voltage at least 120 mV AC (0.12 V AC) on each speaker circuit?

YES: Replace the Amplifier. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Replace the Radio. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test