Another upfitter question

[Cheese22]

I added some bed lights and wired them through an upfitter switch, but I ground the lights to the chassis instead of to the upfitter switch. The lights are not working and I'm wondering if it's because of the ground. I know the ground in the back is good, but does the ground need to be to the upfitter?
TIA, Hoff

 

[The Evil Twin]

Ground is ground. You may not have a solid connection, but any chassis ground is like Connecting to the battery.

 

[Godzilla/Tremornator]

silly questions but just making sure???

do you have the correct up-fitter wire for the switch you are using?

are you using the wires under the hood coming out of the up-fitter fuse box?

the wires in the cab, under the dash aren't hot unless they are connected under the hood.

is the power on for the whole truck?

why are you so certain the ground is good?
any paint will insulate & prevent a good ground!!!!

any chance you have blown a fuse or relay?
swap fuses & relays to check if they are bad.

just trying to brainstorm something you may have missed.

hope you get it sorted out

pics might help someone catch something too

 

[Cheese22]

silly questions but just making sure???

do you have the correct up-fitter wire for the switch you are using?

are you using the wires under the hood coming out of the up-fitter fuse box?

the wires in the cab, under the dash aren't hot unless they are connected under the hood.

is the power on for the whole truck?

why are you so certain the ground is good?
any paint will insulate & prevent a good ground!!!!

any chance you have blown a fuse or relay?
swap fuses & relays to check if they are bad.

just trying to brainstorm something you may have missed.

hope you get it sorted out

pics might help someone catch something too

Yes to all your questions.
I tried all four open switches. I'm using the other two in a similar wiring set up and they work great.
For the ground I wire wheeled the paint off before using a self tapping screw into a side wall in the bed. I'll double check that, though.
No relay since the lights are only a couple small led strips. I didn't check any fuses since it was getting late and I was getting pissed.
Does each switch have their own fuse and where are they located? I haven't really read too much about the fuse location, but I'm sure they'll be easy to find in the daylight.
Pics won't do any good because everything is loomed or taped and run through the frame rails.
I'll post any updates tomorrow.
And thanks for the suggestions.

 

[Cheese22]

Ground is ground. You may not have a solid connection, but any chassis ground is like Connecting to the battery.

Thought so. Just wanted some confirmation. Thank you

 

[Godzilla/Tremornator]

each switch has it's own fuse & relay.

pull the relay of a switch that's working & swap it with the switch that isn't. same with the fuse of each.

reminder
5 & 6 are higher amps
you can also make 5 & 6 live with the truck power off if you change the jumper position in the fuse box.

 

[Canyon Trekker]

I added some bed lights and wired them through an upfitter switch, but I ground the lights to the chassis instead of to the upfitter switch. The lights are not working and I'm wondering if it's because of the ground. I know the ground in the back is good, but does the ground need to be to the upfitter?
TIA, Hoff

I will add some info here. Think of "ground" (chassis or otherwise) as the negative wire; the upfitter feed as a positive wire. Make sure the LED strip is correctly wired in that manner and that the strip light does not have a "constant positive" circuit requirement that turns on with a negative logic. (Ground is switched, not the positive wire)

Part numbers and where you purchased them would really help here to analyze what you have. As @Godzilla/Tremornator points out, the upfitters are not hot unless the key is on. Upfitters 5 or 6 is configurable to stay hot at all times by changing the F4 5A fuse to the "always hot" position.

Upfitters are fused for 25A for position 1-4 and 40A for 5 and 6. If you blew one of those fuses with a "strip light", you may have a bad strip light, incorrect wiring, or as indicated above, negative logic. An LED is basically a diode and if wired backwards, will draw excess current and pop the fuse.

 

[HeavyAssault]

For the ground I wire wheeled the paint off before using a self tapping screw into a side wall in the bed. I'll double check that, though.

Pretty sure the bed isn't a grounded part of the truck. Take your wire off the bed, run it over to the passenger side. Look for the grounding strap near the front tire. Back off the OE hardware, ring terminal onto the grounding stud, use OE hardware to hold ground wire. Done.

 

[The Evil Twin]

Pretty sure the bed isn't a grounded part of the truck. Take your wire off the bed, run it over to the passenger side. Look for the grounding strap near the front tire. Back off the OE hardware, ring terminal onto the grounding stud, use OE hardware to hold ground wire. Done.

Interesting. This, I did not know. Makes sense. There is not a grounding strap to the bed that I have noticed. There is a medium sized ground point under the bed, on the frame at the rear drivers side. Right by the spare tire. Maybe that’s the best location.
@Canyon Trekker has a good point on polarity, too.

 

[Cheese22]

Lot's of great info I'll check out later. Thanks guys!

 

[MrFancypants]

Pretty sure the bed isn't a grounded part of the truck.

I can’t remember precisely where, but there is a factory ground screw on the passenger side frame rail under the spare tire. I used it for my hitch lights and snaked the positive inside the frame rail all the way to the engine bay.

 

[Cheese22]

Sidenote: I saw a ground between the frame and body while I was running an upfitter wire and can't believe how small the ground wire is. I think it was near the back part of the cab and it couldn't have been any bigger than 14g wire.
I read mixed reviews about the Big 3 upgrade, but seeing that wire makes me think a larger wire has to help.

 

[Apples]

I added some bed lights and wired them through an upfitter switch, but I ground the lights to the chassis instead of to the upfitter switch. The lights are not working and I'm wondering if it's because of the ground. I know the ground in the back is good, but does the ground need to be to the upfitter?
TIA, Hoff

Forgive me if you've already done this, but if you have 20' of 14 or even 16AWG handy, run your bed lights' ground back to your upfitter loom's ground? as a test.

That said, CanyonTrekker's advice posted earlier is great advice, especially the reminder to [make certain] "...the strip light does not have a "constant positive" circuit requirement that turns on with a negative logic. (Ground is switched, not the positive wire)"

Cheers.

 

[Canyon Trekker]

Pretty sure the bed isn't a grounded part of the truck. Take your wire off the bed, run it over to the passenger side. Look for the grounding strap near the front tire. Back off the OE hardware, ring terminal onto the grounding stud, use OE hardware to hold ground wire. Done.

The bed does have a "mesh" ground between panels or a small wire that connects to the chassis itself and is at the same potential as the chassis, but the current handling is at a minimum. It's typically good enough for smallish lights but not good for anything drawing a lot of current. The bed is isolated from the chassis somewhat, most likely to reduce noise, and this is why they run the small interconnecting wires to each panel.

Oddly enough, most every component on the truck has two wires running for both positive and negative. The reason is there are multiple control methods that use the negative logic to control things like lights, sensors, etc. or they connect to a common point, avoiding multiple path conduction. (Multiple path conduction can play havoc with electronic components.)

Ideally, grounding to the chassis is best for most applications' small additions for convenience. When using a lot of current, running a heavy gauge wire back to the battery is best. You can run up to ~20A in cases such as a rear power port but may have some loss. For something like a winch or anything needing approximately >40A, always go direct to the battery terminal with a very heavy gauge wire.

I personally prefer running a second ground wire to a terminal block attached to the battery in most all applications. (Dual wire)

 

[Optimus🤖]

Interesting. This, I did not know. Makes sense. There is not a grounding strap to the bed that I have noticed. There is a medium sized ground point under the bed, on the frame at the rear drivers side. Right by the spare tire. Maybe that’s the best location.
@Canyon Trekker has a good point on polarity, too.

I have a grounding strap to the bed.

 

[Canyon Trekker]

I have a grounding strap to the bed.

Watch out for lightning, leather doesn't conduct well; could cause issues.