Hello all,
I have a 2006 F150 6 Cyl AT 149k miles
I noticed my reverse and license plate light weren't working, license plate lights were blown, easy enough. HOWEVER, my reverse lights are giving me a problem. I removed them both, both lights look good, and i'm getting 12V to each connector when in reverse, until i put one of the bulbs in, if i put a bulb in the left or right reverse light, it shorts the other side out, and obviously it kills my voltage, take the bulb out, and my 12V comes back. I've heard it could be the reverse lamp switch on the transmission, but the fact that i'm getting 12V to the connector when in reverse means the switch is working right?

Any help would be appreciated, i use the truck for telecom contracting and am supposed to start a new job Monday.
Thank you!!!
Dan

 

I am having the same issue with my '04. I tried changing the neutral switch but that didn't help. All the wiring at the back of the truck looks good and my tail lights etc. all work fine.

 

rdub,
this is so weird, probably a simple solution, but its really got me stumped. Do you have 12V at the reverse light socket? I found troubleshooting steps on a different forum. The wording gets me confused, but maybe you can make sense of it.
My truck has electrical issues to start with, my fuel pump relay randomly decides not to trip, (its soldered into the fuse box circuit board) my brother didn't realize it was soldered and tried to remove it, thus breaking the outer plastic shell, so i have to take my voltage tester (with key turned on) and manually push the relay contacts together, that and my instrument panel is VERY dim, **** to control will make it dimmer, but not brighter. Anyways, here are the troubelshooting steps



Pinpoint Test T: The Reversing Lamps Are Inoperative

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.

 

The 2 things I would check.

#1, make sure the bulb socket is clean, if you install the bulb and blow the fuse, could be the contacts are getting pressed together.

#2, try a new bulb if you install it and the other one loses + VDC.

BTW : You are checking for + VDC to both the bulb socket ground and to another known good ground when testing ?
- i.e. trailer tow adapter ground if that is in good shape.

 

I have taken all plugs and sockets out, all the way down to just the 2 wires, I bought new bulbs and tried them, as well as jumpering to my brake light bulbs, they do the same thing. And yes, i found a ground, tested the ground, verified it was getting the same 14VDC between it and the hot side of both reverse lights, and tried using that ground along with the hot side of reverse lights to power the bulbs, and it didn't work. I'm going to replace my fuse box and see if that helps, i think the "reversing lamp relay coil" is internal to it, so i'm hoping thats the problem, just kinda skeptical about it considering i'm getting 14VDC to the reverse light socket, i wouldn't think i'd get any voltage if it were bad.. Running out of ideas!!!

 

Hold on, don't do a R&R for the heck of it.

1. What do you mean "reversing lamp relay coil" ?
The truck's reverse lamps are through the DTR to the reverse lamps direct, no relay involved with the truck's reverse lamps.
- The only reverse relay is for the trailer tow adapter reversing ckt, and that is a replaceable relay. Not sure where you got this bit of info from.

2. What do you mean by "jumpering to my brake light bulbs, they do the same thing" ?
Did you cut off the bulb connectors for the stop / turn bulbs and try to use them ?
If so, which wires did you use for the test ( there are 3 of them ).

3. When you are doing the diagnoses, "they do the same thing" means they don't work ?

4. do you have a 7 pin trailer tow adapter ?
- If so when you test, does the voltage "go away" on the pin in the trailer tow adapter as well ?

 

Sorry for the non-technical talk, it actually makes sense in my head while i'm typing it!!
i'm gonna answer these in order to keep them straight
1. I have no clue what reversing lamp relay coil is, according to the troubleshooting steps i posted above it says
"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)"

2. I cut both reverse light connectors down to the bare wire to ensure the connector wasn't corroded, took out the brake light bulb and put the bare wires on the leads to light up the brake light bulb, the brake light bulb did not light up, and it killed my voltage to both the left and right reverse light wires.
I also took the reverse light bulbs and connected them to my brake light wires, the reverse light bulbs light up when connected to my brake light wires (ensuring the reverse light bulbs work)

3. Yes, verified GOOD bulbs will not work when connected to my reverse light wires
4.No, I dont any trailer adapter, didn't even look until after i read your post, but all i have is 4 wires taped up with no connector. They are yellow, green, white, and slate/white
Everything i've read says voltage is supplied by blue/pink to the DTR, then goes to green/yellow which is spliced to black/pink at some point, which is what i have on my reverse light connectors. I'm tempted to jumper blue/pink and green/yellow together, which should bypass the DTR to provide my voltage to my reverse lights to see if maybe the voltage is getting through the DTR but shorting out when there is a load put on the other side, but i'm a telephone repairman, never done much electrical work on a vehicle, so i'm a little nervous to take stuff i've read on the internet as fact... lol
Considering i get 14VDC to the reverse lights until i put a bulb in completely demolishes everything i've learned about electricity, obvious diagnosis is a bad bulb, but the bulbs work when connected to 14VDC provided by a different circuit. Ok, hopefully i explained everything in a manner that makes sense to normal human beings, not just a redneck from East TN. Thank you so much for helping me with this, i really appreciate it!!!

 

The circuit numbers and the diagram, that seems it is talking about the trailer tow reversing relay. Written poorly, as it is to the coil as well as the reverse lamps, parking aid, electrochromatic mirror as well as the truck's reverse lamps.



The only way the VDC on the circuit can go to zero is there is a high resistance path to ground that is shunting the + VDC to it, but it is not enough of a direct ground to blow the fuse ( would be heating up the wiring ).
I don't understand where the 2 would cross at ( high enough of a load to not blow the fuse, by low enough to equal ground ).

I would say time to check the connector for the rear of the truck is in order.

Start with the one that is by the fuel filter ( left hand frame rail, by driver's door ).



In this it is still Dark Green w/ Yellow stripe wire to Dark Green w/ Yellow stripe wire.

Next to check is connector C411 and then C405 if both C3138 & c411 test good.
- Watch C405, that is where the wire transitions from Dark Green w/ Yellow stripe wire to black w/ pink stripe wire.

Use a wire from the battery ground to test with the circuit in the connector.
- Obviously take caution with blocking the wheels, parking brake, etc as you are going to be under the truck with it in gear if you cannot get it on a lift.

This is where I am at, checking the connectors to make sure they will light a bulb when in reverse.
- You can also unplug the connector and apply + VDC to the harness here and check if the bulbs work.

Sorry no magic bullet from me on this issue, time to go old school with divide the circuit and test
- As the old joke goes, make sure you are not one jack off when testing

 

Allright!! good ol' schematic!! Thanks so much for the diagrams, they will help me out a lot! I wish i could tell you for certain that i'm not the jack off, but unfortunately i'm not that confident with auto wiring. Got back from work late today, but i'm gonna go out and scope out the situation and will hopefully report back what i find for anybody else!!! Thanks again!!!!!

 

Ok, so i've been busy, and had to wait out the big storm that hit northern Indiana, but i've done a little bit of troubleshooting, and i'm confused and frustrated!!!
I tested at the small round connector at the back of the truck, i think it was C405. I isolated all the wires and figured out where they were going, toward the back of the truck, the yellow/green wire gets 14VDC when in reverse, HOWEVER it does not light the bulb when connected, and when i turn my headlights on, the polarity switches on green/yellow and ground. Once my headlights are on, the black ground wire is hot, and the yellow/green is grounded!!! WTF???
ALSO......
when testing at the light socket connections the bulb will light up when i connect it to ground on the reverse lamp and hot on the brake light, but does not light up when i connect hot from the reverse lamp and ground from the brake light.
I'm probably doing something wrong, but i triple checked everything i tested.
I'm going to move my way up to the front of the truck tonight, but when i get to the DTR sensor, how do i test it? My truck wont start if it isn't connected, and is there a diagram that shows what the pins on each connector is? As an example, the connector i tested at the other night has Green/Red--Red/Blue--Green/Yellow, and 2 solid black wires. How do i know which black is ground for my reverse lights?

 

You must have been @ Connector C411, C405 the Black w/ Pink stripe is what goes towards the back of the truck ( this is the connector it changes color at ).

Just took a look at my paper copy of the 2006 EVTM, there is only 1 black wire in C411 ( & C405 ) , the other is brown ( parking lamps ).

Is this a DVM meter or one of the Greenlee multi volt auto-voltage or Wiggy type testers ?
- having an issue with how the meter shows + 14VDC on a truck that is not running, and how circuit 1043 has + 14 VDC using the path through the parking lamp element, but when it turns on it is the other way.

 

I have a 03 F150 and my reverse lights don't work. I had my transmission replaced last year. Is it possible they didn't hook something up? It seems that the reverse lights are the only thing that doesn't work..... fuses and bulbs are good.

 

Is the transmission an auto or a manual?

If a manual, then there is one connector, if not plugged in, that will cause a "no reverse lamps" symptom with no other symptoms.

If it's an auto, then "no" because the transmission would shift correctly if the DTR were not connected. Of course, it's always possible that the DTR switch might be defective, that's why there's such a thing as "troubleshooting" that is often required. It replaces something else called "guessing".

 

My transmission is automatic.

 

Then you have your answer regarding something not hooked up.