Something screwy with relays or BCM? HELP!

I need help!!!

So, I've noticed about a month back that when I pressed the brake in, my Tacoma beeps like when I shift into reverse (beeps one time). Then, I was told that that my brake lights also illuminate when I press the brakes. Weird.

Then-when I use my left turn signal it beeps steadily-and won't stop until I turn the turn signal off..but the right turn signal doesn't beep or illuminate wrong lights. My reverse lights also illuminate along with the LEFT turn signal lights.

Weird as that is-last night I was unloading hay out of the back of my truck (I had locked the cab, but went to close the tailgate) and when I accidentally set off the alarm. I noticed that every other loud beep sounded strange, almost like it was struggling to make the noise.

I had a friend who works on other vehicles that it sounds like the BCM might be going out or bad? Has anyone experienced this before? I don't want to spend an arm and a leg to fix it, and depending on what it is-I can do it myself or have someone help me. Anyone have suggestions?

 

That is very unusual where is the beep coming from the dash? Why does it beep going into reverse? Has it always done this? Do you have one of those reverse alarms like on a commercial vehicle?

The brake lights are supposed to illuminate when you press the brake. Not weird at all.

Where is the beeping coming from?

This may be the key to the mystery... I think you have a reverse alarm and the Park Neutral safety switch is indicating that it is in reverse. Look at the dash and see what is indicated.

 

It's not a steady beeping every second-like a commercial vehicle does.... it's one single beep.

I meant my reverse lights illuminate when I press the brakes-so brakes AND reverse lights come on when the brake is pressed. The noise is from inside the dash-it's always beeped once when I shift into reverse (it's a 6 speed). However, there isn't any lights on the dash that indicate the gear you're in.

Because the gear pattern to get into reverse is far left and up-when you shift into reverse the truck beeps once to let you know. Now, that same beeping noise sounds when you press the brake in, and continues (like a commercial vehicle would) while the left turn signal is on-along with the crazy lights. Not sure what it is?

 

As she mentioned, when you shift into reverse in a manual, it let's out a beep to let you know that.

 

Whenever I see really strange electrical issues, the 1st thing I suspect is a bad ground somewhere. If you have circuits that share a ground, and the ground is not connected, you get back feeding between the circuits. Also, when turn signals are involved, it can be a problem with the trailer turn signal/brake light electronic box.

 

Any new leds added around that time? They can make weird crap happen.

 

Learned something new... I have never seen any vehicle that did that and I have driven manuals since I was 15 years old a loooong time ago.

 

I agree it seems to be wiring or trailer connector controller or wiring related...

 

Does your truck have the towing package? I had an issue with my lights, turned out to be the converter box for my 4 pin towing connector. You could unplug the converter box to see if that fixes it. Here is a link to the thread scroll to the bottom for the factory installation PDF for towing kit. Should point you in the right direction, hope this helps:
https://www.tacomaworld.com/threads/turn-signal-light-issue-stays-on-solid.267671/