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Discussion Starter #1
Today I went to install backup sensors for my 2011 RAV4 V6. I think the guy just touched the reverse and rear light parts. After pulling out my car from his garage I found VSC and ABS light became one, which never happened before. I'm not sure if it's coincidence or the guy did something wrong.

Is there any possibility that tapping the reverse light will result to this kind of thing?

Really needs your input! Thanks!
 

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Discussion Starter #2
I used the 4-13 jumper method today and got the following codes:

ABS 49 (Open in stop light switch circuit)
VSC 43 51

The procedure to deal with ABS 49 is attached.

It looks that the ABS 49 is the main problem that results to VSC codes, which is a very common problem. However, mine happened right after backup camera installation which made me think maybe the device (connected parallel to reverse light) screwed up the stop light switch circuit? I used the 8 brakes method to reset and in the morning on my way to work the lights went out but they all came back in the evening. It seemd that maybe the voltage is unstable or something made the stop light switch circuit misbehave.

By the way, my brake lights have no problem at all so I think the switch itself is fine, am I correct?
Any idea?
 

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I had a similar problem once too. It turned out that while working on the taillight converter for trailer lights I'd left a ground wire disconnected by mistake. You might check for something like that.
 

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Discussion Starter #4
Thanks Dy. Dyno. I'll get the guy check the wiring.

In the meantime, I also want to clean the stop light switch but I have no idea how to detach that.

IMG_20171110_053319343.jpg

I pressed the side button of the white connector but still cannot detach that. Can anyone show me how to remove the stop light switch?

Thanks :D


I had a similar problem once too. It turned out that while working on the taillight converter for trailer lights I'd left a ground wire disconnected by mistake. You might check for something like that.
 

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How would you "clean" the switch if you get it off w/o breaking it? That's what happened to the one on my Honda when I tried to take it off for whatever reason. Had to buy a new one.
 

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Discussion Starter #6
I was thinking about spraying some WD-40 into the contacts.

Just arrived my office and found the lights went off in the morning again. Looks that temperature matters !?
How would you "clean" the switch if you get it off w/o breaking it? That's what happened to the one on my Honda when I tried to take it off for whatever reason. Had to buy a new one.
 

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I pressed the side button of the white connector but still cannot detach that.
I believe that you push the white button on the white connector, then pull the connector from the green switch.

Now you can rotate the switch counter clockwise until it can be removed. Next use an ohmmeter to check the resistance between the various pins as described in the PDF you referenced. DO not use WD-40.

To replace the switch, insert it into the adjuster (I assume that is the brown piece) until the switch body touches the pedal (do not depress the pedal). Turn the switch a 1/4 turn clockwise (torque to 13 in pounds or less)

 

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Discussion Starter #8
Thanks, Rick :)

Is it okay to rotate the switch first, take it out and then free the connector? I think the space limited me to do the connector part first.

I believe that you push the white button on the white connector, then pull the connector from the green switch.

Now you can rotate the switch counter clockwise until it can be removed. Next use an ohmmeter to check the resistance between the various pins as described in the PDF you referenced. DO not use WD-40.

To replace the switch, insert it into the adjuster (I assume that is the brown piece) until the switch body touches the pedal (do not depress the pedal). Turn the switch a 1/4 turn clockwise (torque to 13 in pounds or less)

 

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Is it okay to rotate the switch first, take it out and then free the connector? I think the space limited me to do the connector part first.
Well the instructions specify to rotate the switch, and I don't know how many times you can rotate it before the wiring is wound up so tight that you risk damaging something.

In your picture it looks like the brown retainer is just a nut that you could unscrew, but if it is snapped into the metal bracket, then it could not be unscrewed.

Almost all automobile electrical connectors have a latch that hold the two pieces together. In your picture it looks like the white arm dropping into the right side of the green switch is holding the two pieces together. Try pushing that arm so that it moves away from the side of the switch and pull the connector off.
 

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When they say "turn one quarter turn clockwise" that sounds like a bayonet type connector. I don't see any threads anywhere. You should be able to remove it one quarter turn counterclockwise, and then unplug the cable.
 

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Discussion Starter #11
I'm able to remove the stop light and I'll measure the resistance right away before the brake lights eat up all my battery power.
 

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I measured the resistance across 1-2/3-4 before and after switch pressed, the resistance is not the same as the PDF says. Under the condition that it should be measured at 10K ohm it's now showing almost 0 ohm so I think the switch has a problem.

I still have a question, if the switch is faulty shouldn't my brake lights be always on or off? But I don't have a problem with my brake lights.

And, is there any possibility that my backup sensor device damaged the stop light switch?

Thanks :D
I believe that you push the white button on the white connector, then pull the connector from the green switch.

Now you can rotate the switch counter clockwise until it can be removed. Next use an ohmmeter to check the resistance between the various pins as described in the PDF you referenced. DO not use WD-40.

To replace the switch, insert it into the adjuster (I assume that is the brown piece) until the switch body touches the pedal (do not depress the pedal). Turn the switch a 1/4 turn clockwise (torque to 13 in pounds or less)

 

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I measured the resistance across 1-2/3-4 before and after switch pressed, the resistance is not the same as the PDF says. Under the condition that it should be measured at 10K ohm it's now showing almost 0 ohm so I think the switch has a problem.

I still have a question, if the switch is faulty shouldn't my brake lights be always on or off? But I don't have a problem with my brake lights.
The switch has 2 pairs of contacts. One pair will turn on the brake lights when the pedal is pressed, and the other pair sends a signal to the ECM to let it know that your foot is on the brake.

It looks like the circuit between pins #1 and #2 would control the brake lights , while the circuit using pins #3 and #4 sends the signal. Since your brake lights are working, I would expect the problem you detected is between pins #3 and #4 .

There is also another "Brake Pedal Load Sensing" switch, which appears to be located near the "Stop Lamp Switch".

I also don't think you need to consider the 10K ohm resistance a critical value, but only that the switch is closed or opened, and in your case you seem to have a switch that is shorted in the closed position.

The only way the work you did could cause this problem, is if you somehow shorted out the brake light circuit and the excess current welded the switch contacts together, creating the zero ohms condition that you measured.
 

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When they say "turn one quarter turn clockwise" that sounds like a bayonet type connector. I don't see any threads anywhere. You should be able to remove it one quarter turn counterclockwise, and then unplug the cable.
I think the idea is to push the switch in all the way until the switch body bottoms out (i.e. the button is pushed in all the way) and then back it out 1/4 turn to provide the specified 1.5 to 2.5 mm spacing as shown in the figure. Compare the first image to the 2nd image and notice the clearance that was gained after the 1/4 turn.
 

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Discussion Starter #15
The guy did not detach the battery during installation so this kind of thing could happen. However, can I assume that the short condition now does not exist and hopefully when I install the new switch it will not burn out again? If the circuit still shorts now there should be more problems other than this, right?
The switch has 2 pairs of contacts. One pair will turn on the brake lights when the pedal is pressed, and the other pair sends a signal to the ECM to let it know that your foot is on the brake.

It looks like the circuit between pins #1 and #2 would control the brake lights , while the circuit using pins #3 and #4 sends the signal. Since your brake lights are working, I would expect the problem you detected is between pins #3 and #4 .

There is also another "Brake Pedal Load Sensing" switch, which appears to be located near the "Stop Lamp Switch".

I also don't think you need to consider the 10K ohm resistance a critical value, but only that the switch is closed or opened, and in your case you seem to have a switch that is shorted in the closed position.

The only way the work you did could cause this problem, is if you somehow shorted out the brake light circuit and the excess current welded the switch contacts together, creating the zero ohms condition that you measured.
 

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I'm having a hard time believing anything could blow out the switch. But now that you've removed it the issue may be getting it back in in the correct position. As Rick says it has two purposes, operating the brake lights with normally-off contacts and, second, telling the car's computer, the ECU, your foot isn't on the pedal. They're the normally-on contacts which are used to cancel cruise control when you tap the pedal. If the switch isn't adjusted correctly the ECU will be confused thinking the pedal is never released. It responds by setting codes and error lights.
(And we don't even want to mess with the load sensing switch. I thought I had a problem with mine and after messing with it I finally put it back the way it was and all was well again.)
 

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Under the condition that it should be measured at 10K ohm it's now showing almost 0 ohm so I think the switch has a problem.
The switch has 2 pairs of contacts. One pair will turn on the brake lights when the pedal is pressed, and the other pair sends a signal to the ECM to let it know that your foot is on the brake. Since your brake lights are working, I would expect the problem you detected is between pins #3 and #4
Before replacing the probably expensive switch, can you verify that it is pins #3 and #4 that remain shorted, no matter if the plunger is pressed or released, and the #1 and #2 pair behave as expected?
That would confirm that you have performed the test correctly, and the switch is indeed defective.

If the problem is confirmed to be a short between pins #3 and #4 , then it was not likely caused by any work being performed in the rear, since that particular circuit has no relationship to anything in the rear. If the switch pins #1 and #2 had the problem, then yes, the work in the rear was likely the cause.
 

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Discussion Starter #18
I measured it again with the continuity test function (sorry I totally forgot about this). Pin 1/2 beeps when plunger is not pressed and 3/4 beeps when plunger is pressed, so the switch now functions well. However, the floating resistance value does not always stay under 1ohm (0.X ohms to several ohms), which I think might be normal because I can barely measure it in a stable way using probes to touch the pins.

So if the switch has no problem, what's my next step? I've searched a lot on Google and did see that some people had C1249 problem due to brake light incorrect grounding (grounding wire bitten by mice) or trailer lights are added.

My current situation is that the lights are not on when the engine started, only when the car moves the light comes back.


Before replacing the probably expensive switch, can you verify that it is pins #3 and #4 that remain shorted, no matter if the plunger is pressed or released, and the #1 and #2 pair behave as expected?
That would confirm that you have performed the test correctly, and the switch is indeed defective.

If the problem is confirmed to be a short between pins #3 and #4 , then it was not likely caused by any work being performed in the rear, since that particular circuit has no relationship to anything in the rear. If the switch pins #1 and #2 had the problem, then yes, the work in the rear was likely the cause.
 

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I measured it again with the continuity test function (sorry I totally forgot about this). Pin 1/2 beeps when switched is not pressed and 3/4 beeps when switched is pressed,
The problem with a continuity tester is that if the resistance goes above 10-20 ohms it will no longer beep.

If you you have a 25 ohm resistance where you should have infinite resistance, it could still cause a problem. So verify that the resistance is infinity (or at least greater than 10K) under the proper conditions.

At this point I would reinstall the switch and follow the proper positioning instructions.
 

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Discussion Starter #20
The multimeter I borrowed showed 0ohm under the circumstance when the resistance should be >10K ohm, but if I switched that to continuity test right away it would not beep. Maybe I need to get another multimeter since this meter will auto-detect ohm range instead of being manually set.

The problem with a continuity tester is that if the resistance goes above 10-20 ohms it will no longer beep.

If you you have a 25 ohm resistance where you should have infinite resistance, it could still cause a problem. So verify that the resistance is infinity (or at least greater than 10K) under the proper conditions.

At this point I would reinstall the switch and follow the proper positioning instructions.
 
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