I am wiring my tail lights into the military lights that came with the trailer donor as my flatbed. Two questions, first, are the lights grounded by wire to the frame? I don't see a black grounding wire in my loom for the tail lights (I have a cab and chassis). Second question, is this correct:
Green wire with orange tracer = turn/stop driverside
Orange wire with blue tracer = turn/stop passenger
Brown wire = Running/marker lights for both sides
Black wire with purple tracer = Reverse light (both sides).

 

Your wire colors are correct. There is a ground wire shown below. Connector c123 is at the rear. Splice 903 is near the fuel guage sender along the frame rail. Connector c124 is at the lower left dash panel. Splice 805 is near the cigarette lighter. Ground G701 is behind the radio under the dash on the firewall.

 

Could you explain those grounds a little better? Is the entire ground system wired together? Or are they simply grounded to the chassis in different locations. My manual is showing all the rear lights funnel into a junction labeled S13 via C66, C71, C69, and C67. Not sure what these numbers mean. Could you school me? Thanks.

 

The Flaresides and Cab & Chassis trucks did not have ground wires to the taillights, they were grounded directly through the three mounting studs to the frame (cab & chassis) or directly to the mounting brackets/bed (Flareside).

See below, both 1984 and 1985 diagrams show the grounding point at the taillights, but the license plate lamp did get a dedicated ground wire (my 1984 has this, but my 1980 does not).


And here is 1985, no change...


Here is what I did with mine on both Flaresides. I ran a dedicated ground wire from the frame to each of the rear taillights, and connected it to the lower left mounting stud. See below:



The original lights were made by Grote (and still are, if you can find replacements), and they still have no ground wire...the mounting studs are the ground. These same lights were also used on the cab & chassis trucks, as far as I know.

In any case, the quick and easy solution is to run a ground wire to the frame for each light, or wire them into the trucks grounding wires somewhere else. My 1984 had a ground wire in the rear harness for the license plate lamp, but my 1980 did not. Hope that helps.

 

Thank you very much for the clear explanation. The “ground blocks” in the manual are a little confusing. They seem to suggest that all the grounds meet at a particular location, but it’s not clear where. I will run dedicated grounds to each light as you have.

 

That's the quickest/easiest solution imho.

 

They do all meet to a single ground behind the radio. That is G701. I believe Rembrant is mistaken, if he looks in his diagrams, the tailights are grounded to G107. Unless G107 moved, it is still behind the radio.

 

From the 1985 diagram, G701 is still behind the radio.

 

In the 1985 diagrams I did find another ground on the dually pickups with the wide fenders. They have marker lights in the fenders and the 3 marker lights in the middle. These did use another ground back there, G903

 

No, not mistaken. You are correct about the Styleside trucks, but the Flaresides and Chassis cabs did not have a ground wire to the tail lights...it's shown right in the 1984 and 1985 EVTM pics I posted above. You can see the grounding point is AT the taillight housing...see below: The central grounding point was only in reference to the Styleside trucks. This is a fairly common issue with the Flareside trucks....people are always trying to find the ground wire, and they can't, because there never was one...

 

I can't debate with you when all I have is the factory diagrams. They can be full of mistakes in various places. A single grounding point is usually labeled a certain number. So if they followed their labelling theme, each taillight ground would have a different number. But like I said, they diagrams can have mistakes.

 

LOL, but there's nothing to debate...it's right in the official Ford diagram that the cab & chassis trucks and Flaresides did not have a ground wire to the taillights. I posted it for you guys...see the yellow arrow...the lights are grounded AT the light, via the mounting studs. The red arrow shows how the Styleside trucks were wired...WITH a ground wire. This is a really common issue Franklin, and it pops up semi-regularly when owners cannot find a ground wire for the taillights...it's because there never was one, even from the factory. You are correct in your statements, but only about the Styleside trucks. The factory style taillights used on the C&C trucks and Flaresides were made by Grote, and they didn't have a ground wire, so Ford never ran one to them.

 

The G107 in your diagrams are throwing me off. I did miss in the top diagram the little ground symbols right at the light symbol. I will agree with you on that.

But the license marker light still has a G107 ground. That should be labeled something else if it's truly a separate grounding point back there. Cruising quickly through the diagram with it being labelled G107, and it even has a gap in the drawing suggestion that is shorthand, skipping the details and connectors and how it gets to G107. Not knowing there is no ground wire going up front, I would assume G107 is up front like the rest of the diagrams show

Styleside without bumper has the same problem. There is that G107 again.

You guys using the frame as ground; Make sure you have the factory ground wire with the grounding band bolted to the frame. Or make sure you have a decent sized wire going from the engine block to the frame. The frame IS NOT grounded unless you purposely ground it. The engine is grounded from the battery. But the engine/transmisson/transfercase/rear leaf springs are all mounted in rubber. So there is no ground path to the frame unless you make one. Even the exhaust system is hanging in rubber mounts..

 

Oh there is a ground wire going from G107 all the way to the rear of the truck, at least there is on my 1984, but it only goes to the license plate lamp, same as it shows in the diagram. My 1980 F150 doesn't have this wire...so it must have been added sometime after 1980 (on the Flaresides at least). The tail lights were grounded to their mounting brackets, which were grounded to the bed...imagine...can you think of a worse grounding point??...A Flareside bed...with a wooden floor, mounted on wooden blocks sitting on top of the frame. They came from Ford that way. I've heard reports that Ford did start adding a ground wire like I did with mine, but it wasn't until late 1985 or sometime in 1986.

My trucks are well grounded...one of the first things I did with both was run all new ground cables and wires, and cleaned all mounting points to shiny bare metal...even including the little ground wires on the inside of the fenders by the front marker lights. My 1984 F150 had a factory ground wire from the battery to the frame to the engine block. I've replaced this, same as factory, on both trucks. I think if you have all good grounding wires, you will have minimal wiring issues (or at least fewer than most Bullnose owners).

Anyway, the cab & chassis trucks were the same way, considering that when Ford built them, they didn't know what was going to be on the back of them.

 

I’m trying to find replacement tail lights for my 83 F350 CnC do you know a part number or anywhere to buy ones that will plug into the existing wiring harness in the back?