E 450 V8-5.4L (2009)
-
Is the voltage greater than 10 volts?
Yes
REMOVE the known good relay. INSTALL a new trailer tow parking lamp relay. TEST the system for normal operation.
No
REMOVE the known good relay. GO to U4.
-------------------------------------------------
U4 CHECK THE PARKING LAMP INPUT CIRCUIT TO THE RH TRAILER TOW STOP/TURN RELAY FOR AN OPEN
-
Measure the voltage between the trailer tow parking lamp relay pin 1, circuit CLS30 (VT/WH), BJB face side and ground.
-
Is the voltage greater than 10 volts?
Yes
GO to U5.
No
REPAIR circuit CLS30 (VT/WH) for an open. TEST the system for normal operation.
-------------------------------------------------
U5 CHECK THE VOLTAGE SUPPLY CIRCUIT TO THE RH TRAILER TOW STOP/TURN RELAY FOR AN OPEN
-
Measure the voltage between the trailer tow parking lamp relay pin 3, circuit SBB57 (RD), BJB face side and ground.
-
Is the voltage greater than 10 volts?
Yes
GO to U6.
No
REPAIR circuit SBB57 (RD) for an open. TEST the system for normal operation.
-------------------------------------------------
U6 CHECK THE VOLTAGE SUPPLY CIRCUIT TO THE RH TRAILER TOW STOP/TURN RELAY USING THE RELAY GROUND
CIRCUIT PIN
