backup lights Quit Working

[Curious Hound]

That is correct.

Once the circuit is supplied by a fuse, it rarely ever goes through another fuse in automotive circuits.

There is no reason for a relay since the reverse lights are the only load on that part of the circuit and they dont draw much current. So, basically, the flow of power is this;

Fuse at SJB >> DTRC>> reverse lights >> ground

Sometimes a fuse will power several similar circuits. Don't let that throw you off track. And, yes, the circuit will go through multiple connectors and splices. This is necessary to make it possible to install the wiring through the firewall, frame, other tight spots at the factory.

 

[Joe2808Range]

That is correct.

Once the circuit is supplied by a fuse, it rarely ever goes through another fuse in automotive circuits.

There is no reason for a relay since the reverse lights are the only load on that part of the circuit and they dont draw much current. So, basically, the flow of power is this;

Fuse at SJB >> DTRC>> reverse lights >> ground

Sometimes a fuse will power several similar circuits. Don't let that throw you off track. And, yes, the circuit will go through multiple connectors and splices. This is necessary to make it possible to install the wiring through the firewall, frame, other tight spots at the factory.

Well im glad to hear that, i was hoping i didnt have a burnt inaccessible CJB relay. so it sounds like the DTRC isn't putting out power or i might have a short, but if so wouldn't the fuse keep tripping ? or even a disconnected connector.?

 

[Curious Hound]

A short will most often blow a fuse. A "short" or short circuit is when there is no resistance in the circuit. Like when you just take a piece of wire and connect it from positive to negative on a battery with no motor or light or anything else to use the power. Zero resistance equals infinite current. That causes melted wiring and fires. So don't do it. If a positive wire rubs through it's insulation and touches ground, that causes a short circuit.

When a wire is broken in a circuit or a switch is turned off or the fuse is blown or connector is disconnected. That is called an "open circuit". In this case, there is no complete circuit or path for current to flow. So, voltage comes from the source and when it gets to the open spot, it stops and nothing else can happen in the circuit until the problem is fixed.

So in your reverse light circuit, power comes from the battery through the fuse and then goes to the DTRC. There, it stops until you put the transmission in reverse. This closes a switch contact and completes the circuit, allowing power to travel to the reverse lights where "work is done", converting electricity into light and heat. The ground wires complete the circuit path back to the battery negative terminal.

If your fuse is good, and all the wiring is good, you should have battery voltage on the appropriate wire at the DTRC. Once you put the transmission in reverse, you should have battery voltage coming out of the reverse switch part of the DTRC on the other wire (usually pink/black on older Ford trucks. But your diagram, if correct indicates a different color). If you have battery voltage there, then you should have it at the positive terminals of your reverse lights. If not, there is a loose connection or broken wire somewhere prior to that point.

I'm curious about how the wire for your camera was tapped into the reverse wire. Did you do that yourself? Or did someone else do it?

 

[Joe2808Range]

A short will most often blow a fuse. A "short" or short circuit is when there is no resistance in the circuit. Like when you just take a piece of wire and connect it from positive to negative on a battery with no motor or light or anything else to use the power. Zero resistance equals infinite current. That causes melted wiring and fires. So don't do it. If a positive wire rubs through it's insulation and touches ground, that causes a short circuit.

When a wire is broken in a circuit or a switch is turned off or the fuse is blown or connector is disconnected. That is called an "open circuit". In this case, there is no complete circuit or path for current to flow. So, voltage comes from the source and when it gets to the open spot, it stops and nothing else can happen in the circuit until the problem is fixed.

So in your reverse light circuit, power comes from the battery through the fuse and then goes to the DTRC. There, it stops until you put the transmission in reverse. This closes a switch contact and completes the circuit, allowing power to travel to the reverse lights where "work is done", converting electricity into light and heat. The ground wires complete the circuit path back to the battery negative terminal.

If your fuse is good, and all the wiring is good, you should have battery voltage on the appropriate wire at the DTRC. Once you put the transmission in reverse, you should have battery voltage coming out of the reverse switch part of the DTRC on the other wire (usually pink/black on older Ford trucks. But your diagram, if correct indicates a different color). If you have battery voltage there, then you should have it at the positive terminals of your reverse lights. If not, there is a loose connection or broken wire somewhere prior to that point.

I'm curious about how the wire for your camera was tapped into the reverse wire. Did you do that yourself? Or did someone else do it?

I did the canera and it's worked that way for 3+ years now, until this abs / brake light issue has happened.

After I put this self resetting fuse I think somewhere in the circuit I may have damaged a wire since it was unable to blow the fuse, but I was unable to notice the light even coming on when I did this, so I assumed it wasn't even popping anymore.

When I remove that fuse, the abs / light still illuminates.

But, I still don't know if my Abs / brake side is ok at this point.

I have a feeling it's this abs circuit that's blowing other circuits on this fuse.

 

[RobbieD]

I did the canera and it's worked that way for 3+ years now, until this abs / brake light issue has happened.

Check your connection point(s) for the camera, too.

If you used a SctotchLock type quick-connector, those can cause issues, especially after some time.

 

[Joe2808Range]

Check your connection point(s) for the camera, too.

If you used a SctotchLock type quick-connector, those can cause issues, especially after some time.

View attachment 123860

I don't believe it's my camera connection, my camera is hardwired into my Radio by my dash, the trigger wire when 12v is received turns on the camera. But I can manually push a button on my radio to turn on my camera.

 

[Curious Hound]

I don't believe it's my camera connection, my camera is hardwired into my Radio by my dash, the trigger wire when 12v is received turns on the camera. But I can manually push a button on my radio to turn on my camera.

When we talk about your camera connections, we are blanketing all camera connections - power, ground, image signal and reverse trigger signal. All the wiring for the camera system.

I also agree about those scotch-loc connectors. They are pure evil.

 

[Joe2808Range]

When we talk about your camera connections, we are blanketing all camera connections - power, ground, image signal and reverse trigger signal. All the wiring for the camera system.

I also agree about those scotch-loc connectors. They are pure evil.

Sorry I don't quite understand. So, you're saying. you're ignoring the camera connections.

I agree with what you're saying with that and no, my connections are either Soldred, Butt connection, End Crimped or Male to Female spade connectors for Future removal if I need to disconnect them for any reason.

I think if I remember, the camera connects to a wire that runs back to the radio and a seprate trigger wire runs from the radio to the back.

When I go in reverse, the trigger wire receives 12v and goes to the backup camera wires at the dash and activates video.

 

[RobbieD]

I don't believe it's my camera connection, my camera is hardwired into my Radio by my dash, the trigger wire when 12v is received turns on the camera. But I can manually push a button on my radio to turn on my camera.

I think that you said the camera trigger was connected to the reverse light circuit.

Scotch-Lok connectors "bite" through the wire plastic insulation; in theory the copper wire nicely falls into a slot in the connector's metal blade. But usually the strands get some damage, being nicked or severed. Another factor is that a Scotch-Lok isn't weatherproof; over time air and moisture causes "green rot" in the copper strands at the connection. The green rot eventually reaches a point where the copper wire fails as an electrical conductor, or even breaks.

The insulation may not break, but downstream after the Scotch-Lok the circuit will be dead as a doornail.

It's something worth checking, even if it just eliminates the connection from the troubleshooting. And, it is a common factor between the B/U lights and camera, both of which are not working.

 

[Joe2808Range]

I think that you said the camera trigger was connected to the reverse light circuit.

Scotch-Lok connectors "bite" through the wire plastic insulation; in theory the copper wire nicely falls into a slot in the connector's metal blade. But usually the strands get some damage, being nicked or severed. Another factor is that a Scotch-Lok isn't weatherproof; over time air and moisture causes "green rot" in the copper strands at the connection. The green rot eventually reaches a point where the copper wire fails as an electrical conductor, or even breaks.

The insulation may not break, but downstream after the Scotch-Lok the circuit will be dead as a doornail.

It's something worth checking, even if it just eliminates the connection from the troubleshooting. And, it is a common factor between the B/U lights and camera, both of which are not working.

Yeah No, I never liked using those wire Taps. I've always Crimped my connections.

And Right now, until I can check my wires underneath. I am dead in the water.

I don't want to keep bothering you until I find this out first, when I figure this out. I will post back with an update.

 

[Curious Hound]

Sorry I don't quite understand. So, you're saying. you're ignoring the camera connections.

No. The opposite. When we talk about your camera connections we are talking about all the connections that have anything to do with making the camera function. I'm sorry my wording was confusing.

Glad that you did not use scotch-locs.

Even crimp connections can give trouble later on unless covered by heat shrink with sealant inside. That is to keep water out so they don't corrode.

 

[pjtoledo]

I had posted info based on a 2005, your 2008 has a few differences. sorry about the confusion.
some connectors and the wire colors are different.
the basic circuit is the same.
power leaves F-20, goes thru the DTRS and on to the rear lamps.

I would split the circuit at the DTRS
check continuity & send power into the output wire. use a fused hot source, like a power probe.
verify 12v at the input wire.

 

[Joe2808Range]

I had posted info based on a 2005, your 2008 has a few differences. sorry about the confusion.
some connectors and the wire colors are different.
the basic circuit is the same.
power leaves F-20, goes thru the DTRS and on to the rear lamps.

I would split the circuit at the DTRS
check continuity & send power into the output wire. use a fused hot source, like a power probe.
verify 12v at the input wire.

I apologize but what do you mean by split the circuit and where.do I check continuity ?

I wish I had a power probe but I don't

I had posted info based on a 2005, your 2008 has a few differences. sorry about the confusion.
some connectors and the wire colors are different.
the basic circuit is the same.
power leaves F-20, goes thru the DTRS and on to the rear lamps.

I would split the circuit at the DTRS
check continuity & send power into the output wire. use a fused hot source, like a power probe.
verify 12v at the input wire.

Well, I made Good progress. I think this may be my problem. I haven't tried to see if I have power out but I verified power In.

I guess the 12v input wire just didn't get affected but the other wires did.

I need to find this connector and solder it on.

 

[pjtoledo]

good find.
sometimes a thorough inspection is what's needed. I liken that to exploratory surgery.
that harness looks repairable with butt connectors, due to the location it won't be easy.

"split the circuit" simply means pick a convenient point between A & B and open a connector/something for diagnostics.
a switch, the DTRS, is a good point because one side is power coming in, the other is going to the load.

I'm damn near 72 and fully realize how fun this stuff is.

 

[Joe2808Range]

good find.
sometimes a thorough inspection is what's needed. I liken that to exploratory surgery.
that harness looks repairable with butt connectors, due to the location it won't be easy.

"split the circuit" simply means pick a convenient point between A & B and open a connector/something for diagnostics.
a switch, the DTRS, is a good point because one side is power coming in, the other is going to the load.

I'm damn near 72 and fully realize how fun this stuff is.

Actually, when I pulled off that connector. It's thend leading to the vehicle away from the transmission and I have around 1-2 feet wire I can work with.

I'm gonna check Spaldings to see if I can find that harness.