HuntO

Hey guys, this has stumped me for a while. Both my reverse lights have quit working. I replaced the bulbs and fuses, and still nothing. I've searched all over the web, and haven't found a good answer as to what this could be. Anyone have any idea as to where to start to fix this? I work night shift, and it sucks trying to back up in pitch black. It's a 04 F150, new body style. It also has the tow package, and trailer wiring if that makes a difference.

Thanks in advance!

Mod (Ret.)

Found this test procedure for an '05 F150:

Normal Operation

Switched battery voltage is normally provided to the digital transmission range (TR) sensor through circuit 295 (LB/PK). When the transmission is placed in REVERSE, the digital TR sensor routes power to circuit 1043 (DG/YE) which provides power to the reversing lamp relay coil. The reversing lamp relay is integral to the central junction box (CJB). When the reversing lamp relay is energized, power is routed from the central junction box (CJB) to circuit 140 (BK/PK). Ground is provided to the reversing lamp relay by the CJB and each lamp through circuit 57 (BK).

Possible Causes

circuit 140 (BK/PK) open
circuit 295 (LB/PK) open
circuit 1043 (DG/YE) open
CJB
digital TR sensor

PINPOINT TEST T: THE REVERSING LAMPS ARE INOPERATIVE
Test Step Result / Action to Take
T1 CHECK FOR POWER TO THE DIGITAL TRANSMISSION RANGE (TR) SENSOR
Ignition OFF.
Disconnect: Digital TR Sensor C167.
Ignition ON.
Measure the voltage between the digital TR sensor C167-9, circuit 295 (LB/PK), harness side and ground.

Is the voltage greater than 10 volts?
Yes
GO to T3.

No
GO to T2.
T2 CHECK CIRCUIT 295 (LB/PK) FOR AN OPEN
Ignition OFF.
Disconnect: Central Junction Box C270b.
Ignition ON.
Measure the voltage between the CJB C270b-1, circuit 295 (LB/PK), component side and ground.

Is the voltage greater than 10 volts?
Yes
REPAIR the circuit. TEST the system for normal operation.

No
REPAIR or INSTALL a new CJB. TEST the system for normal operation.
T3 CHECK REVERSING LAMP OPERATION
Ignition OFF.
Connect a fused (10A) jumper wire between the digital TR sensor C167-11, circuit 1043 (DG/YE), harness side and the digital TR sensor C167-9, circuit 295 (LB/PK), harness side.

Ignition ON.
Do the reversing lamps illuminate?
Yes
INSTALL a new digital TR sensor. REFER to Section 307-01.

No
LEAVE the jumper wire connected. GO to T4.
T4 CHECK CIRCUIT 1043 (DG/YE) FOR AN OPEN
Ignition OFF.
Disconnect: Central Junction Box (CJB) 270b.
Measure the resistance between the CJB C270b-1, circuit 295 (LB/PK), harness side and the CJB C270b-12, circuit 1043 (DG/YE), harness side.

Is the resistance less than 5 ohms?
Yes
GO to T5.

No
REPAIR circuit 1043 (DG/YE). TEST the system for normal operation.
T5 CHECK FOR REVERSING LAMP RELAY GROUND
Ignition OFF.
Disconnect: Central Junction Box (CJB) C270f.
Measure the resistance between the central junction box C270f-6, circuit 57 (BK), harness side and ground.

Is the resistance less than 5 ohms?
Yes
GO to T6.

No
REPAIR or INSTALL a new central junction box (CJB). TEST the system for normal operation.
T6 CHECK CIRCUIT 140 (BK/PK) FOR AN OPEN
Disconnect: LH or RH Reversing Lamp.
Disconnect: CJB C270e.
Measure the resistance between the CJB C270e-20, circuit 140 (BK/PK), component side and LH reversing lamp C451-3 or RH reversing lamp C461-3, circuit 140 (BK/PK), harness side.

Is the resistance less than 5 ohms?
Yes
GO to T7.

No
REPAIR circuit 140 (BK/PK). TEST the system for normal operation.
T7 CHECK CIRCUIT 57 (BK) FOR AN OPEN
Measure the resistance between the LH reversing lamp C451-1 or RH reversing lamp C461-1, circuit 57, harness side and ground.

Is the resistance less than 5 ohms?
Yes
REPAIR or INSTALL a new CJB. TEST the system for normal operation.

No
REPAIR circuit 57 (BK). TEST the system for normal operation.

Other possibilities:

Check the DTR ( Digital Transmission Range ) Sensor on the side of the auto trans.
Pin #11 on the DTR connector same Dark Green with Yellow stripe wire.

check the trailer tow reverse light fuse (its a 20 amp fuse in postion 10. Passenger side kick panel).

HuntO

Thank you! I'm going to go ahead and check the fuse in position 10, but if that doesn't work, i'm thinking i'll just replace the DTR. It's only the reverse lights that don't work. Would i be safe to bet that it's most likely the DTR? If it's not that i'd just replace the CBJ. How difficult is it to replace the DTR? I can't seem to find a walkthrough on the net. Although it looks like a pretty simple part. Are there any specific tools required to replace the DTR?

Thank you again!