2014 CM SR5 - "panel" fuse blowing, no HVAC control lights, stereo not dimming

Hi all - I want to start by saying how great this forum is! Got my tundra about a month and have been learning a lot through these threads.

2014 SR5 Crewmax. I noticed first that my stereo wasn't dimming when I turned my headlights on and didn't think anything of it. I thought maybe this was a feature the truck didn't have. Then I realized the lights for the HVAC knobs and all switches, etc. didn't come on with the headlights. Again, thought it was a missing feature. This weekend, I installed the AJT Design blackout kit and saw a bunch of LEDs and diffusers behind the HVAC controls and realized something wasn't working.

After some tundras.com digging, I thought maybe the problem was the day/night mode setting in the head unit. I was unable to access the setting no matter what I did (parking brake on/off, etc.). I also tried to rotate the odometer reset knob on the instrument cluster. It changes the brightness of the instrument cluster (when the headlights are on), but nothing else in the cab. The parking brake light turns on in the instrument cluster when the parking break engages, so I know that the parking brake engagement signal is working.

I tested every single fuse in the interior fuse panel and one fuse was blown, a 7.5amp fuse labeled "panel". I replaced the fuse and it immediately blew again. I assume related to my problems.

Note that all of the electrical in the truck is original except for an aftermarket trailer brake controller that was professionally installed. I found one thread that said someone was having a similar problem with an aftermarket trailer brake controller, but it didn't help me troubleshoot. I pulled apart the dash and looked where the trailer brake was installed, and it seems pretty straight forward, I don't see how it would relate to my problems. And the trialer brake is working correctly.

All that said, my questions are as follows:
1) At the risk of asking the obvious, it is a safe assumption that whatever is causing the blown "panel" fuse is causing my HVAC control panel lights to not work when I turn on my headlights?
2) How would I determine what is causing the fuse to blow?
3) At what point do I need to get professional help diagnosing this, and where should I go? Dealer, car stereo installer, etc. If I do bring this in to get worked on, any idea how much $$ for something like this?

Thanks in advance!
Steven

 

Did you buy it from a Toyota dealer?

 

No, private party.

 

I removed the brake controller, fuse blown. Out of curiosity, I disconnected the HVAC controls AND the head unit AND the brake controller all at the same time...fuse blown immediately when I turned the headlights on.

 

I've got 2019 pro headlights and iHacker harness in the garage. So I will be working on them soon.

This is a bit new to me. What/how would I check the headlights here?

 

Maybe remove the headlights from the equation?

 

On my truck the “panel” fuse is a 5 amp. Are you sure it’s the panel fuse?

 

It's definitely the "panel" fuse. And the fuse box cover has it labeled as 7.5 amp, which was also the fuse size that I pulled out.

I will remove the headlights from the equation and post the result. Probably will just do it when I install the PRO headlights.

 

Reason I asked was because I had a similar issue. My AC panel crapped out on me while I was in the Grand Canyon. I have the dual climate with the digital temperatures. The numbers shut off and the AC stopped blowing. If your AC still works it may be because yours is probably the analog climate control? Anyways, turned out that I had a chafed wire that was shorting it. As soon as I got off-road, the bumps would make the chafed wire rub against the metal body panel and pop the fuse. But it wasn’t the panel fuse. Can’t remember exactly which fuse but it was one of the 10amps. The wire was one of the wires in the bundle of wires going from the engine fuse box into the driver’s side firewall grommet. The Toyota tech spent about 3 hours checking and unplugging everything that was on that wire harness. When that didn’t work, he started looking for a bad wire and got lucky when he noticed the fuse kept popping when he wiggled that wire bundle. Might be worth taking a look at that wire bundle.

 

@joonbug You are correct that my AC still works and I have the analog climate control. As best as I can tell, everything works on the truck as expected except what I mentioned above.

Thanks for the suggestion on where I can look next. I really appreciate it.

 

I’m bringing back this old thread. I still haven’t solved this problem. Would it be possible to wire my gage cluster to my HVAC and stereo for dimming? This would bypass the blown fuse.

I haven’t found anything else that isn’t working with this fuse. Trailer lights all still work.

 

Yes, the panel fuse is the cause for the loss of illumination for all those items, plus some.
Quick search shows:
24 PANEL 7.5 A: Instrument panel lights, glove box light, ashtray, accessory meter, audio system, rear view monitor, navigation system, rear seat entertainment system, gauges and meters, air conditioning system

Most likely culprit is mentioned above, somewhere in the various harnesses going to all those systems, you have an abraded wire grounding. The other is a straight short circuit in any of those systems (less likely, but possible). If I were you, I'd disconnect everything on that list and replace the fuse. If it blows you've got a grounded wire somewhere. If it doesn't, you've got a short circuit somewhere, start adding components you disconnected back into the harness until it blows, thats your culprit (hopefully the only one).

Im pretty sure it means the light associated with the components listed, except for maybe the ashtray, which I assume they mean the cigarette lighter.

 

I know it’s not a short circuit, as I already tried removing the components as you suggest and the fuse still blew. I’m struggling to figure out how to find the grounded wire, and certainly open to suggestions.

Would it work for me to “bandaid” the problem by splicing the stereo and HVAC panel lights dimming wires to my dash gauges that still dim?