Braking and Lights/Radio Power go out

Here is a strange one for you (2017 OR Long Bed). So about two month ago I started experiencing random problem where the radio would shutoff when braking. The dealer has attributed it bluetooth and did a radio flash, ecu flash, etc, but it continues. The main problem is that when I take it is they cannot reproduce it since it does not happen all the time. Once it starts on a trip it will do it until i turn the truck off and restart and that sometime makes it to that is stops doing it, but not always. Trying to get some ideas from the community of where to start looking since I am out of warranty (45k) and tired of paying for diagnostics that do nothing.

Symptoms:
When hitting the brakes the radio turns off
the headlights dim or fliker off and on
Sometimes the dash goes dark and then comes back on

I was able to reproduce in neutral one time in which case the entire engine shutoff. Given this I am thinking the engine kicks everything back on

I am thinking a ground short, but don't even know where to start. Love the truck, but this is driving me crazy.

I have some video I can post if any one wants to see, but it will be next week as I am travelling.

 

You have any rodent damage, body work done or rust issues? Sounds like a bad ground.

 

The armchair mechanic in me says charging system or battery. Battery cables clean and tight?
Have the battery load tested.

 

Sounds like a ground or power issue. Brakes have electrical boots on some models, to they will consume a lot of power. I’d start monitoring battery voltage at different points in the trucks wiring when you get the problem. Or, just replace the battery as a quick shot in the dark and check the main grounds for corrosion.

 

It wouldn't hurt to check and see if there is voltage drop under load between the battery posts and the cables themselves.

 

lets go over the easy stuff first, Battery has been load tested and is good ? battery connectors removed,cleaned, properly reinstalled, especially the ground. what you are describing is an intermittent bad ground, or a battery that is experiencing an internal short.

 

So to answer questions
1. Battery has been tested and tests good under no load and load. May replace anyways just to be sure
2. 45k so out of warranty hence trying to figure this out
3. Yes there was damage to the front right hand side 2 yrs ago and it was repaired and checked by toyota, and I have checked that area also looking for anything that could be out of place/mis-repaired.
4. No LED's
5. No rodent damage that I am aware of and don't live in an area with a lot of them, unless you count redskins fans

 

If ground and voltage is good...the only other thing I can think of that has commonality with brakes, meter and radio; is the CAN BUS.
Though, it should throw a U-type DTC if that were the case.

 

Anybody have a wiring diagram for one of these things?

 

So at this point I think I am going to do the following.

1. replace the battery with a new battery just to rule that out
2. Start tracing grounds ( does anyone have a good diagram?)
3. hope it goes away

 

I have a 94 f350 and after cleaning and spraying deoxit on the grounds I have no electrical issues. It may have a few years on our tacos though.

 

FWIW, after skimming the below diagrams, I doubt it's a grounding issue.

 

Have you had the alternator tested?
Trailer brake installed on the truck?

 

I have not had the alternator tested yet, but will add that to the list of things to do.

 

So before I took it in I was checking the oil and noticed that the battery hold down had become loose and there was some terminal corrosion. I cleaned the battery terminals and tightened the battery hold down. This seems to have corrected the issues I was having. 200mi and not issues so far.

 

Years of working on cars has taught me to always check the simple stuff first.
Happy it was a cheap repair for you.