Jakeepoo3
New member
Check for bad wires and open grounds. Loose over spread female terminals.
Brake lights constantly on?
- Thread starter rwh963
- Start date
Check for bad wires and open grounds. Loose over spread female terminals.
been keeping my eye open for animal damage, discolorations, loose stuff, etc. i'm gonna check the terminals on the brake switch plug (i did change the switch at 200k, maybe something happened). everything looks normal in the fuse box.
Jakeepoo3
New member
That's a good idea. Hopefully there no rust damage UNDER the relay/fuse box. Also with a test light or multimeter. You can't see the whole circuit.
BlackWorksInc
New member
Did you pull the Tail fuse and stop fuse individually to see if there might be voltage leaking into the circuit somewhere else? (Start with the Stop fuse first, then reinstall it and pull the tail one)
not sure. i'll revisit that later. did you mean the STOP relay?
picked up some brake fluid and moved the level closer to MAX. no effect. was thinking while driving, when do VSC/TRAC lights come on? when you are engaged in heavy braking on loose surface? is there some sensor that is malfunctioning that is thinking i'm in a situation like that? i'm not feeling any braking occurring while driving (like ABS). maybe need a computer re-flash?
BlackWorksInc
New member
You likely have some DTCs stored from the diagnostic steps you took. More than likely codes for the stop lamp relay, the stop lamp switch, etc. You can reset the vehicle by disconnecting the battery for about 5-10minutes. In some rare cases you may have to do a zero point calibration (not as common on the '05+ 4Runners, the '03~'04 vehicles had slightly different ABS modules that seemed to forget ZPC if you looked at them wrong. lol)
gm350reratliff
New member
I've been following along with your issue for a while. I think you need to revisit the trailer tow plug and/or wiring. I mean like really inspect it for any signs of contacts touching inside the plug but especially inspect it for any signs of water intrusion and/or corrosion. Especially the back side of the plug where the factory harness plugs into it - very common to get water in there. Unplug it and see if the issue is the same. Work your way forward from that plug. I would pull the 30 amp trailer power (trailer battery) fuse and see if that changes anything.
Jakeepoo3
New member
The ABS light comes on when brake fluid is out of range not the VSC. The stop lamp switch is an input to the skid control ECU once again.. causing the light and deactivation of your abs related functions. That system activates when one or more of your tires are skidding or spinning out. Have you checked the grounds in the circuit at least?? Sh!t can tend to operate backwards with key on/off with an open ground. You can't just guess and ask people what their experience is or you'll never fix it. You're beginning to overthink and question circuits not even involved.. You need to get a test light and multimeter out partner before someone smashes your ass end
Jakeepoo3
New member
Why would disconnecting the battery do anything??? That just clears codes at least a few of them. They instantly come back if you didn't fix the problem.. if your using the dealer at least go in acting like you know what you're talking about so you don't get f_cked. I would put a $20 bet on an open ground or loose fuse or relay feminine terminal. You said you replaced the stop switch at 200k. I'm not sure with your year where that ground is located but did you reconnect the ground?
Jakeepoo3
New member
If you were local if charge you half price
hey,
the switch is simply plugged into the harness receiver. there was not a separate ground to deal with.
i'm not sure why a female terminal would be involved since i've never done any fuse replacements. i've pressed in all the fuses, did a continuity test on all type A fuses, don't see any issues with any wires anywhere.
the brake booster was replaced with a used unit at 110k miles.
no other electrical abnormalities.
Jakeepoo3
New member
Just because the fuses are good with continuity doesn't mean they're plugging in tightly.. "no other electrical anomalies" so it's definitely in that little loop. That's what's cool about a test light. It'll tell you the fuse and plug in for it is good at the same time.
Jakeepoo3
New member
If you just have a multimeter test for battery voltage also across the fuse to make sure the f_ckin terminals are contacting... I'm not sure what else can help you. Did you check the ign fuses too.
was too busy to stop at the dealer today. did unclip the brake switch from its harness and used a test light to check the power few through it. with the key off and the key on, same result: in the pic, the lower left and the upper right generated light. didn't see any loose wires anywhere under the dash. also, reiterating that the brake lights run with or without the switch even attached with the key on.
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BlackWorksInc
New member
Next time you get a chance and the issue is happening, pull the 10A TAIL fuse under the dash and let us know if the issue is gone with the fuse removed.
I'm wondering if maybe your Flasher/DRL "Relay" (it's actually more of a small module than a relay) has an issue or if that circuit is back feeding into your brake lamp circuit.
I'm wondering if maybe your Flasher/DRL "Relay" (it's actually more of a small module than a relay) has an issue or if that circuit is back feeding into your brake lamp circuit.
Jakeepoo3
New member
PHP:
What did the other terminals do? Can you get a picture of the wires/color behind the connector also? Don't take it to the dealer and disrespect yourself sorry but you can do this yourself. Post the pics I think I have the same circuit set-up. I don't know what they're teaching you in college but a little electrical engineering should be a f_cking requirement!
thx. the issue is always happening! i actually did pull the 10A tail fuse, and also separately the 15 A IGN1 fuse. the tail fuse had no effect (brake lights and VSC/TRC lights on full time). btw, the VSC dash lights come on as part of the start up check. they go off for a moment, then reappear. the brake lights do not go off and then reappear.
pulled the IGN1 15A fuse, VSC lights go on as usual, then disappear as they should, and brake lights DO NOT go on. put in a new 15 A fuse, no difference.
Maybe something in the ignition switch?
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using just the test light, the other two terminals did not light it up in any key mode. positives and grounds?
sure, i can post whatever pics you want! btw, i would not feel any negative emotions getting shop assistance. wouldn't want to pay much, and could possibly do the repair myself, but this diagnostic step is taking everyones time. we all want an answer!
