Installing tailgate lock, lost power to lights, possible BCM or ECU damage?

Well, I've been slacking thinking that I can live without the headlights by just driving during the daylight and the power locks by using the key....
However, quickly realized that sucks.... so I am going to tackle this electrical mass I created step by step no matter how long it takes....

A few things I've done so far...
1. Check every single fuses on the truck, which turned out all good.
2. Had the dash completely out without a clue then put it back in.

Where it all started was when I shorted the Pin 3 & 4 on MJ1 connector...

Problem confirmed so far are
1. Power door locks not working. remote, switches, nothing.
2. Low beam headlight not working.
3. Fog light stays on. headlight switch not working.
4. Windows only working when the car is running.
5. Interior light not turning off when the doors are closed.

with these problems going on I need to figure out what are the common factors,
I am going to start with the headlight issue since it's the biggies problem..
wish me a good luck... smh....


<Original post below....>
Hello fellow tundra owners, I just ran into a huge problem myself and need some advise.
I was installing a tailgate power locking and tapped into the passenger side MJ1 connector white and blue wires, believe they are 3,4. anyhow while playing around with the wiring, suddenly power locking and headlights and interior lights are lost checked some fuses by pulling them out but no obvious blown fuses. Did I damage the BCM or ECU? for some reason fog lights are staying on for some time and go off after a while. Any advice will be appreciated. thank you.

 

There have been threads on the correct wires to tap into for the locking tailgate.
You obviously tapped into the wrong wiring..
I'd suggest you disconnect what you connected, disconnect the battery for 15 or so minutes, and then see what you have going on.

Don't forget you have 2 fuse boxes, at least I think for your 2008..
1 under the hood and 1 under the dash..

You can always find the wiring diagram for your truck here..

Ultimate TUNDRA Wiring Diagrams Collection | Toyota Tundra Forum (tundras.com)

Good luck..

 

@1lowlife thanks for the tips I'm planning on rechecking all the fuses again. [/B][/SIZE]

 

Updates.
Checked all fuses I can possibly find more then twice and they are all good.
Problem still having.
1. Power locks not working w/remote, from master switch, none
2. Head lights don't turn on but high beams turn on with switch pulled but not pushed away.
3. Fog light stay on regardless of key in the ignition and buzzing sound from driver's fuse box while they're on.
Stays on for a while then turns off. after like 5 mins.
4. Interior lights stay on unless I switch them off with light switch.
I am lost and don't have any clue where to start since all fuses are good?
Battery has 12.4V and the truck starts and runs fine with above problems..
should I just take it to the dealer?
wish I was something simple...
Any help will be appreciated.

 

One thing that all of those problems have in common is the blue MJ1 and NJ1 connectors, located in the kick panels.
Those connectors contain several ground wires for different things, as well as power to others.
That sounds like it might be your issue.

You already know where they are.
Is it possible that either you cut a wire or it isn't fully plugged in?
Or maybe a wire pin came out of the connector while you were moving wires around?
Try making sure everything is fully seated and plugged all the way in.

I would think if an ECU was fried there would be more stuff going wrong.
But I'm not a mechanic.

Good luck..

 

While checking my headlight circuit noticed 5.9v on one of the prongs. Shouldn't it be a ground??

 

Did you start but unhooking the wiring that you added in? That should be the first step.

 

@Jeff_5_7 Hi Jeff, plug n play connector that I used is now off. I think what had happened was 2 wires I used(in the red box) got shorted. what could be fried if those 2 are shorted...?
I am going to test the plugs at the drivers junction box tomorrow and see what's off using alldata chart.

 

Are you absolutely sure your fuses are good? Interior fuse box was check thoroughly?

The 25A DR/LCK looks like a good candidate to be bad here...

 

As far as I could tell the fuses are good. I took the driver's fuse box out to do the testing but I am very confused at the moment doing ohm testing.
2 major issues I'm having now is headlights and power door lock.
with the head lights. fuses are good and non of the 15a fuses under the hood is getting power? they are grounded all times.

 

They won’t be powered until the headlight relay is closed. The body control module closes the relay when the headlight switch comes on, when this happens power goes through the 15a fuses to the bulbs.

If the headlights are off (relay is open) the 15a fuse will be dead in the water

 

I need to find a way to bench test the body ecu. hope it’s possible.

 

Why bench test? You will never be able to fully "replicate" all of the truck on the bench.

Put it back in the truck and test with a multimeter, while it is installed and the key is on

 

Yes sir I will re-install the box back in truck. I am currently studying up on some youtube videos for electrical wiring.. let’s see how this works.

 

While you have it out thoroughly test every fuse with a multimeter. I can easily believe your entire problem is due to a bad fuse.

 

I don’t know this is the right way to describe but there is 6v flowing on the connector DB on 16 & 18 with both HEAD & DIM relays out is this normal you think?

 

Does it change to 0V (ground) when the headlight switch is turned on?

 

Headlight switch is not functional as it doesn't turn lights on or off. I am lost in the ocean and pulled the dash out to check all the wiring just for the sake. if I don't see anything obvious. I don't know what else to do next..

 

yellow hight lighted wires should have 12v all time?? when I check the v at the door switch connector both only shows less than 12v and when I hit the buttons they drop. if getting less than 12v is the issue then it may be the ecu…

 

Hard to know forsure but yes most likely these should be 12v. Reasons why I was saying make sure you really check all the fuses. A bad one could mean only partial power to the circuit.

6V seems odd, could be an internal failure in the BCM. I have never seen one fail before.

 

I did get the techstream and the main body ecu is not communicating with the program.. been looking at the alldata to find how to diagnose this issue.. hmm...

 

As I have said several times before verify all power into the ecu. 99% of miscommunication with ECUs on Techstream is because they are not properly powered.

Fuses, Grounds ect.

If it is properly powered and will not communicate you most likely have an internal failure.

 

Will do, I will check the power and ground thoroughly once again.

 

Could be worth the gamble to buy another ecu on eBay for a few hundred $$. Verify part number matches.

Plug it in and see if it works, if you really think you have an internal failure.

 

If I do replace the body ecu, does it need to be reprogrammed?

 

Problem solved.

It was the Body Ecu itself.. used unit from ebay fixed my problem... SMH
Thanks Jeff for all your help.