Suddenly last week I got stuck in park and no brake lights. Changed brake light switch and found fuse 25 blown. Replaced the fuse with another 15A and it lasted for just a bit... then blew. Replaced with 25A fuse (I know... not the best idea) because I needed to get home. It blows the 25A fuse. I mean a hard blow of the fuse.

So what lights and all are on that fuse? Have tried searching but not found a good answer.

Also, the other weird thing is I replaced the radio about a month ago. Has worked perfectly. The same night the fuse blew, I started getting noise out of the tweeters. It stops around 30MPH. Sounds like power filter noise, kind of. It does not correspond to the engine RPM. Almost sounds like it is arcing or something is. Is anything on the radio power tied to that fuse?

I am trying to troubleshoot but hard when all I know is the brake lights and a hard short like that is not good.

 

Fuse 25 is part of the interior and exterior lamps circuit...


And the shift interlock circuit...

 

what did you find out?

 

Yesterday I stopped on the way home and couldn’t shift out of park. Found video on solenoid release button, got home and remove the brake switch. Purchased new style brake switch from autozone, original LR part.

New brake switch did not work. Then sourced the blown fuse to F 25 under steering column. Put a new fuse in, retried the new brake switch, did not work. Tried theold brake switch worked for a few seconds and then blew of F 25.

Tried the testing pin1 to pin 3 on brake switch connector with a fresh fuse, blew the fuse.

Pulled off the tail lights, top left had one bulb blown. The right had one bulb almost blown. Removed the third brake light, which has a previously warmed up housing noticed when replacing a bulb two years ago, the black lead doesn’t look great.

Any suggestions?

 

I checked all fuses even remotely involved - F14 under hood, F4, F11, F29, F33 inside the truck all are ok.

 

Did you read the install instructions for brake switch, you have to partially install switch, then depress pedal and turn brake switch another quarter turn..or it will not work.

 

There is no instructions in the box

 

so the short seems to becoming from the third brake light not working.

 

Corrosion/burnt spots like that can also cause increased amp load on the circuit which could blow the fuse if it is already near it's capacity at full draw. I would try replacing the female spade and cleaning up the male spade with some sandpaper. Put some grease on the connection. It will act as a dielectric and prevent arcing which will slow or stop more burnt spots from forming, only allowing direct metal to metal contact to carry current.

 

Everything seems to work with the third light bulb socket removed.

I found some LED third light units in smoke, red and clear. It looks like the female connectors need to be changed to male. Would also pull less current. Has anyone used these?

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