B - Both RH & LH Mirrors Inop. (Without Memory Mirrors)
Pinpoint Test B: Both RH And LH Mirrors Inoperative - Town Car (Without Memory Mirrors), Crown Victoria, Grand MarquisB1 - Check Mirror Supply Circuit 54 (LG/Y)
- Remove outside rear view mirror control as outlined.
- Disconnect outside rear view mirror control harness connector.
- Using a voltmeter, connect one lead to circuit 54 (LG/Y) and circuit 57 (BK) at outside rear view mirror control connector.
Is B+ present?
YES GO to B6.
NO GO to B2.
B2 - Check Ground Continuity Circuit 57 (BK)
- Connect an ohmmeter between circuit 57 (BK) and known good ground. Measure resistance.
Is resistance 5 ohms or less?
YES GO to B3.
NO SERVICE circuit 57 (BK) for open. RESTORE vehicle. RETEST system.
B3 - Check Supply Circuit 54 (LG/Y) For Voltage
- Using voltmeter, measure voltage at circuit 54 (LG/Y) and a known good ground.
Is B+ present?
YES GO to B6.
NO GO to B4.
B4 - Check Supply Circuit 54 (LG/Y) For Short To Ground
- Using an ohmmeter connected to a known good ground, connect second lead to circuit 54 (LG/Y).
- Measure resistance.
Is resistance 5 ohms or less?
YES SERVICE circuit 54 (LG/Y) for short to ground. RESTORE vehicle. RETEST system.
NO GO to B5.
B5 - Check Supply Circuit Continuity
- Check continuity of circuit 54 (LG/Y) between outside rear view mirror control and fuse 17 (10A) Town Car, fuse 4 (15A) Crown Victoria, Grand Marquis.
Is resistance 5 ohms or less?
YES REPLACE fuse 17 (10A) Town Car, fuse 4 (15A) Crown Victoria, Grand Marquis. GO to B6.
NO SERVICE circuit 54 (LG/Y) for open. RESTORE vehicle. RETEST system.
B6 - Check Mirror Switch Operation
- Using a jumper wire, jump circuit 54 (LG/Y) to appropnate circuit.
- Connect a second jumper wire to circuit 542 (Y) and a known good ground.
- Observe operation of each outside rear view mirror as jumper is applied
Did mirrors operate properly?
YES REPLACE outside rear view mirror control. RESTORE vehicle. RETEST system.
NO GO to B7.
B7 - Check Switch Output For Short To Ground
- Using an ohmmeter connected to a known good ground measure resistance of each circuit per chart below.
DRIVER SIDE
Circuit Function
541 (DB) UP
542 (Y) DOWN
542 (Y) RIGHT
540 (R) LEFT
PASSENGER SIDE
Circuit Function
544 (P) UP
545 (W) DOWN
545 (W) RIGHT
543 (DG) LEFT
Is resistance 100K ohms or more?
YES REPLACE suspect outside heated rear view mirror. RESTORE vehicle. RETEST system.
NO SERVICE suspect circuit for short. RESTORE vehicle. RETEST system.