94 F-Superduty Tail lights

[ISPKI]

Hey ya all.

I am just about ready to mount my flat bed onto my new F-Superduty. Its a 94 7.3idi. I searched around for a few pages but wasnt seeing anything clear for a cab and chassis.

The back of the electrical harness was cut and spliced and yadda yadda back at the rear of the truck. Whoever did it, did a clean job of it, weather sealed connectors, terminating in ring terminals, routed into a weather proof junction box with distribution studs. Problem is, the spliced wires dont match the factory harness and now that ive removed the fiberglass utility bed, I need to wire in lights for my logging flatbed.

I have found the factory wires about midship and labelled the spliced colors. These are the colours in the factory harness;

Green w/ Orange stripe - Left Turn?
Orange w/ Black stripe - Right Turn?
Black w/ pink stripe - reverse?
Brown - Brakes?
Black - running lights?

Can anyone correct me on these? I was referencing my F250's wires but not sure if the cab and chassis are identical or slightly different?

Lastly, does anyone have suggestions for tail lights? I have some 2.5" round lights but theyre pretty crusty and many dont work so I was thinking about getting new ones. I was looking at these: https://www.amazon.com/Partsam-Reve...dp/B017W818HG/ref=psdc_15737741_t3_B07PVPLCSH but I dont know if they are decent or not. Reviews seem good except for one guy saying they let water in the housing.

 

[chillman88]

Here's what I used when I replaced all the lights on my trailer. I'm very happy with them!

Amazon.com

Amazon.com

Amazon.com

Amazon.com

 

[Big Bart]

Ditto on Chillman on my trailer.

More and more box trucks and flatbeds are moving to those oval led tail/brake lights. Then use clear/white oval ones for back ups. (If you drive at night a lot, perhaps two sets of clear for more back up illumination.) Or one set of back ups and add wire in spots on your lumber guard or under the your rear of your bed so you can better hook unhook trailers, load, unload, etc. at night.

They are sealed, water tight, low amps (LED’s), bright, easy to find at stores, easy to replace. (pop out our a rubber gasket and have a pop off connector.) They also sell kits with both colors.

They sell multiple kinds. Some are solid brake or flash. Others the middle is flash and the outside stays solid in a brake and turn situation as I recall. Some are brake, flash, reverse all in one. I just have it where the whole light is brake or flash.

Amazon.com

Amazon.com

 

[ISPKI]

I had a set of surface mount ovals and they were hot garbage. Annoying to mount, immediately leaked water and the mounting points broke shortly after. How do those flush mount ovals mount up? Does the rubber grommet just press into a hole and stay in without any fasteners? Maybe that was my issue with previous ones.

I ordered up a set of 8 flush mount 4" Round lights and a dozen single LED amber marker lights. Going to run those around the perimeter of the bed, aim some down and some out to illuminate the underside of the bed. Might order up more and mount them up the back arch to light up the whole bed area as well.

Whats the good word on those tail light wires? The truck side harness does not have a ground in it right? The lights have to ground to the frame at the back of the vehicle?

 

[chillman88]

How do those flush mount ovals mount up? Does the rubber grommet just press into a hole and stay in without any fasteners? Maybe that was my issue with previous ones.

Yessir.

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Nice and bright too.

Sorry I can't help with the wire colors though.

At least on the pickups, the light harness grounds to the frame at the rear. I don't THINK there's a ground in the harness. I know they won't work if you forget to reconnect that frame ground!

 

[ISPKI]

Looking good there Chillman. Did you form those panels yourself or did you have a shop do them? Are the holes laser or plasma or waterjet cut?

I just got the 4" round lights, quality seems far better than the surface mount ovals I had before and I now see how these things mount up. Little flange in the rubber grommet so it slips over the lip of the cutout and wont fall out.

I am debating between using a 4.5" hole saw or cutting the holes with a laser instead.

 

[ISPKI]

I suppose, what I could do with the wiring harness identification is turn the truck on and start flipping switches and just test the wires one by one with a multimeter to confirm their function.

I made a new common ground point bolted to the rear most cross member which I then coated in plastidip and undercoating. All the rear grounds will route into the sealed junction box, should keep everything clean and orderly.

 

[chillman88]

Looking good there Chillman. Did you form those panels yourself or did you have a shop do them? Are the holes laser or plasma or waterjet cut?

Thanks! I just drew my measurements out and one of the guys at work cut them out on our laser table. Sure is handy! Especially since I don't have a plasma cutter at home

 

[Scotty4]

You could make your own jig for a plasma cutter using a ruler, hoseclamp, and pointed piece of 10ga. Layout hole centers, center punch, then walk the torch in a circle keeping the pointed piece in the center punch. Bing bang boom.

 

[ISPKI]

Nice, now I need to get a plasma cutter.

 

[ISPKI]

So I did a fair amount of wiring and testing and came up with the following for the tail lights;

Orange and Green wires have 10.60v with running lights on, Brown has 13.60v.

With left turn signal on, Green pulses up to 13.60v, Orange still has 10.60v.

Right turn signal on, Orange pulses up to 13.60v, Green has 10.60v

With brakes depressed, both orange and green have 14.50v

Hazard switch on, both orange and green pulse 13.60v

Truck in reverse, Black w/ Pink stripe has 13.60v.

Tail lights seem to be;

orange w/ stripe: Right Turn/Brake signal
Green w/ Stripe: Left Turn/Brake Signal
Brown: Running Lights
Black/Pink Stripe: Reverse lights

The black wire seems to have continuity to ground so apparently the harness does have a ground that travels back to the front of the vehicle. Just seems odd that it would head all the way back to the front when they could just ground to the rear of the frame but maybe that is for a fuse.

 

[notenuftime]

So I did a fair amount of wiring and testing and came up with the following for the tail lights;

Orange and Green wires have 10.60v with running lights on, Brown has 13.60v.

With left turn signal on, Green pulses up to 13.60v, Orange still has 10.60v.

Right turn signal on, Orange pulses up to 13.60v, Green has 10.60v

With brakes depressed, both orange and green have 14.50v

Hazard switch on, both orange and green pulse 13.60v

Truck in reverse, Black w/ Pink stripe has 13.60v.

Tail lights seem to be;

orange w/ stripe: Right Turn/Brake signal
Green w/ Stripe: Left Turn/Brake Signal
Brown: Running Lights
Black/Pink Stripe: Reverse lights

The black wire seems to have continuity to ground so apparently the harness does have a ground that travels back to the front of the vehicle. Just seems odd that it would head all the way back to the front when they could just ground to the rear of the frame but maybe that is for a fuse.

I'm rewiring my taillights right now, put a flat bed on putting LEDs in.

My questions is with the solid black wire, where did you tie it in? Far as I can see it tied in with the running lights.

 

[ISPKI]

I'm rewiring my taillights right now, put a flat bed on putting LEDs in.

My questions is with the solid black wire, where did you tie it in? Far as I can see it tied in with the running lights.

I ended up connecting it to a common ground point on the rear most crossmember in addition to keeping it in the harness. I dont know exactly where it goes in the harness, just that it runs back up front into the cab somewhere inside the dash.

It has been some years though and I have some stuff to button up on the truck. I'll try and get under it this week and take pictures of where I connected it.

 

[notenuftime]

I ended up connecting it to a common ground point on the rear most crossmember in addition to keeping it in the harness. I dont know exactly where it goes in the harness, just that it runs back up front into the cab somewhere inside the dash.

It has been some years though and I have some stuff to button up on the truck. I'll try and get under it this week and take pictures of where I connected it.

This is my factory plug for my license plate light.

It looks like it was tied into there,black to black

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I was going to wire it into that, figured it was the ground.