need help with diagnosing tail light issues on a freightliner fl80

[tacomabanga19861986]

we have a rescue truck that is a freightliner fl80 i think is the model


for some reason we cant figure out why the tail lights dont work


ive went through all the fuses on the passenger side fuse panel


either there is another fuse panel somewhere else, or a wire has be cut and it would be a pain in the u know what to find where its cut at


we've checked the bulbs and there fine, i even checked the tail light wire with a test light and no voltage is going to it at all


its kind of a major issue due to most of our calls are at either dusk, nighttime, or when we clear scene its dark out and theres no tail lights to the rear of the truck


brake lights work fine, just the tail light section of it doesn't work


i have looked all i can on google for a wireing schematic for this truck and couldn't find anything remotely close to it


i would be more than happy if anyone could help with this due to it being a safty hazard, and its 2nd out truck to a car wreck


im pretty good with electrical stuff so if someone told me how to do it, or go about fixing it, im sure it will get done


if it comes down to it i might have to run a new wire from front of truck off side markers and "tie in" to the wires in the back and terminate the other ends of wires


i hope this is readable enough to figure out my problem, and i do appreciate any help in resolving this problem

 

[Turd Ferguson]

Speaking from nearly 10 years as a trucker, and most of that running freigtliners, the moist common cause for in/op tail lights is a broken wire. I usually find the break inside the split loom at the back of the frame. On many FL models, just before the tail lights, they bundle up the loom and zip tie it. Thus causes a sharp bend which, over years of bouncing around, causes a break right there. Have a look and get back to me if it's not there.


Edit: you might also find some green corrosion around the break. If that's the case, and I'm sure you already know this, chop all the bad stuff out, and put in extra if you have to cut it that short.

 

[Turd Ferguson]

Just curious on how things are going with this. Got tail lights yet?

 

[tacomabanga19861986]

havent had time to fix it, or diagnose it


its a fl70 i think is what i read on the side


i think im just going to brake down and run a new wire from front to back and piggie back off lights and cut off old wire and tie in to wires on lights


i'll check what you said though


and today i found out that the company that had this truck before us gutted it before we got it, and it had to be redone, so that might be an issue


the lights are weird sometimes lol

 

[Turd Ferguson]

havent had time to fix it, or diagnose it

its a fl70 i think is what i read on the side


i think im just going to brake down and run a new wire from front to back and piggie back off lights and cut off old wire and tie in to wires on lights


i'll check what you said though


and today i found out that the company that had this truck before us gutted it before we got it, and it had to be redone, so that might be an issue


the lights are weird sometimes lol

Just be careful about tapping the marker lights for that. A lot of times Freightliner has separate fuses for each, so be careful you don't overload, causing repeat fuse pops.