What’s wrong with my truck

Okay so my buddy’s brake lights on his tundra quit working and I tried to figure it out so I checked all fuses and they where all good then I replaced the brake light switch and now when I try to start the truck it just cranks and if I press the brake pedal the abs light, stability light come on and the vsc light also starts flashing. The maintenance required light also was on but I reset it and every time I try to check the codes my code reader can’t connect to the truck. I tried unplugging the battery to let everything reset with no luck I’ve tried to adjust the switch and I have power to the big wire on the switch and the small turquoise wire but still have the same issue the truck will go into gear no problem but just won’t start. Any help would be greatly appreciated!

 

Check for lose ground wire, or rodent damage in wiring

 

Any suggestions on which ground wires to look at? Because I didn’t mess with any ground wires and the truck started and ran before I did anything

 

Did you try putting the old brake light switch back in? If the new switch is bad, I suspect other major systems might not work if it doesn't get the thumbs up from the switch.

 

Yes I did sorry forgot to add that part but when you’re adjusting the switch is there a certain way to do it? Also if anybody knows what the wires go to would be nice to know as well I think the colors I have are black (little wire), red (big wire), turquoise (2nd biggest) and I forgot the other wire color but it’s also a small wire. I have constant 12v on turquoise & red btw but nothing on the others

 

You might find some help in the wiring diagram for the model/year of the truck. This link may have what you need.

https://www.tundras.com/threads/ultimate-wiring-diagrams-collection.81448/

 

What year is the truck. The stop light control relay works with the skid control ecu. Sounds like somthing is backwards if all the skid control warning lights are coming on when the brake is applied

 

It’s a 2007 tundra and the lights will only come on if I press the brake pedal then they stay on

 

This is where your focus should be. The Blue and Orange wires go to the stop light switch. Blue will be hot all the time from battery, Orange is only hot when the switch is close to send power down to the lights.

Double check the 15A Stop fuse and the 7.5A ECU-IG Fuses

 

Okay will do thank you and I’ll let you know what I find out

 

The Black and Red wires are for a signal to the Engine ECU of the brake pedal status. Almost looks as if Black will be hot 24/7 and Red will be hot as long as the pedal is no pressed. When you push the pedal Red looses power telling the ECU the brakes are being applied. I think that is how this switch is setup to work.

The part with the tail lights is still the blue and orange. Blue is hot 24/7, when switch is closed from hitting pedal orange is hot to go light up the bulbs.

 

Black is being sourced by the ignition, so it would only get power when the key is in as opposed to 24/7 like the blue wire?

If this is the case, OP needs to clarify the state of ignition for each of the tests he runs and results. But I also may be misinterpreting the drawing.

 

All tests have been performed with the ignition on acc. Also any ideas why the OBD2 won’t recognize on my code reader?

 

Good catch, I didnt notice it was an ingtion controlled fuse.

 

Do you have power at the OBD2 port?
Pin #16 is 12v power from battery. Goes through 7.5A OBD fuse.

 

The key might have to be in the "ON" position. I seem to recall every time I put an OBD2 on, I would put it in the first position which is ACC. And it wouldn't work. But when turning the key one more click to "on", I think it worked.

You posted that blue and red wires were posting 12V when you tested, but black was not. What were you using as ground reference? These measurements were with the switch removed and you were probing the truck's wire harness connector? If so, odd that red would post 12V.

 

I meant I had the ignition on “on” not acc my mistake but the obd 2 port still wasn’t working I will check the pin #16 I know the fuse is still good and also I wasn’t using the black wire as ground reference I just back probed it while it was plugged into brake switch

 

I’m sorry red wasn’t pulling 12v the big orange wire was and the blue wire

 

I came in to post this.

I bet the ECU fuse is fried.

 

Where’s the ecu fuse? In the cab or under the hood?

 

Stop fuse is #9 under hood.

ECU-IG 1 fuse is #47 in the cab under the driver dash.

As mentioned, you should also check the other ECU fuses. I attached the pages from the owners manual to make it easier to figure out which ones.

 

1) Are your brake lights coming on when you depress the brake pedal? Do they go off when the brake pedal is relaxed?

2) With brake pedal not depressed there should be power at the red wire position 4 at the switch.

3) That switch is a double throw switch when on leg of switch moves the other switch leg moves also. So when brake pedal is relaxed their should be no voltage at the orange wire position 1. With brake pedal depressed you loose voltage at the red wire position 4 and gain voltage at the orange wire position 1. If this does not happen then either you have a bad switch or a broken wire. ECU's are very hardy.

4) You should always have power at blue wire position 2 and black wire position 3 at brake switch. Unless you have a broken wire.

Your quote should be normal with brake pedal depressed. Relaxed should be the opposite. Power at red and no power at orange. If the power does not change in the relaxed position then you have a bad switch. All this is with the key in the on positon.

So according to your OP it sounds like there is a disconnect between switch position 3 and 4 and or a broken red wire or a "bad ECU not the most likely". You are probably getting all the warning lights because there is a disconnect between position 3&4 and or a broken wire.