ISSUE: Installed Ditch Lights, now Clock and Radio backlight turns off when headlights are on.

just checked the tail fuse, not it.. even had a spare 15A and swapped them out with no luck..

 

From what I gather from other reading... The 2020 Head Unit switched out harness connectors. They appear to be completely different from prior years.

I have the same Anytime Backup Camera setup too. I ordered back in January and I do not recall having to select a model year... However, my unit was different than yours; Especially, with the blue and grey wires NOT being part of a connector harness. Yours appears to tap into the Head Unit Illumination Circuit and May have done something wonky like what has/is been/being described here.

I used the VSC Switch circuit for illumination to tap my loose blue and grey wires with Posi-taps.

Maybe, as something to try to diagnose would be to “de-pin” those to wires from the HU connector?. If it restores your back lighting then maybe take those wires to backlight your switch on another “friendly” switch for illumination?.

 

Well, I am buttoning my dash back together.. will have to try again perhaps tomorrow =/

 

Hmm. So have you also checked the Parking fuse? I also saw someone else mention the Dome fuse being associated with the illumination circuit.

 

Get a fuse tester and test ALL fuses in both boxes. That should be step #1

 

I pulled and checked fuses visually.. but that sounds like a good tool to invest in. I will try to handle that on all fuses tomorrow before trying anything else.. thanks Joon!

 

@SC_TRD did you have any luck yesterday?

 

Hey! So didn’t get to tinkering with it yesterday found myself busy all day installing new leaf springs and shocks in the rear of the truck...

but just finished playing with it with my new tester I bought @joonbug and kind of figured it out, or at least made progress..

In the cab fuse box, there is a 7.5A fuse called “panel” that was not registering any current.. so popped the fuse out and tested the actual fuse slot and there was also no voltage.. funny thing, when the fuse is pulled out clock and radio do not turn off when the headlights are on... but I replaced with a nearby 7.5A fuse that was good and then the problem occurred again ... so right now I am running with no fuse in this location as it appears to be dead, but I am also fairly certain this did not fix the rest of my interior buttons not lighting up... definitely not sure the best approach to figure this all the way out

 

Do the interior fuses get fed by any of the relays and fuses under the hood? I think I had a wiring diagram on my computer at one point but it's been deleted...

 

good thinking! I am definitely not certain, but I know my new glow handle tester will tell me quickly.. One of the good things about WFH in all this, I can tinker at any point in the day... post back in a few.. and I’ll also do some research on this idea. Thanks @TRDFerguson!

 

Well, checked under the hood and seems like all exterior fuses are good. Let me do some research to see if maybe I missed something that is feeding into the interior fuse box. Maybe I can dig up a wiring diagram like you mentioned. Thanks again!

 

Did you figure out your issue? Now I’m afraid to tap into anything for dash light on my switches.

 

I ended up pulling one of the fuses underneath in the cab to solve the problem.. think it was the accessory fuse.. still my backlighting won’t work on any nob though =(
but the radio screen at least lights up

I can take a picture to confirm fuse later if you want