RS Help Please

[DMP 10+ year member]

BTW, the right brake wire should be 0 volts at rest and 12 volts when you press the brake pedal.

 

[daboyfrumdabx 10+ year member]

sounds like its a bypass problem

Nah, definitely related to the LED tails. If I unplug the tails, I have no issues. If I leave the brake wire disconnected I have no issues. Some diodes should cure it.

BTW, the right brake wire should be 0 volts at rest and 12 volts when you press the brake pedal.

I have the right wire. It reads 0V at rest and 12V when pressed if I unplug the LED tail lights. With them plugged it immediately reads near 2V once I start the car and climbs until the car shuts off. Like I said, I have it doing what I want it to now that I grounded that wire. I'm pretty confident that once I diode isolate that wire, I'll be in good shape. I'll update tomorrow...or today rather...how it goes if I get the chance to mess with it.

One diode should do it. I think I just need a diode between the Viper connection and the car...not between the Viper and the brake switch itself. This way if the brake really is pressed, the Viper can still get the 12V to shut off and no voltage backfeeding from the tail lights can reach that wire. We'll see what happens.

 

[x1le 10+ year member]

The diodes really won't do much I don't think. That problem sounds strange though. If the voltage on your switch is slowly rising, is it also engaging your brake lights on it's own?

But the easiest way to fix this issue, without messing with the taillights in any way, is if you also have a wire that goes to ground when the brake pedal is pressed. Then just change the polarity of the brake wire with a relay. 85 - (-)brake wire, 86 & 30 - 12v, 87 - (+)brake shutoff from brain

 

[daboyfrumdabx 10+ year member]

Just finished up the diode idea and it's working so far. The tail lights turn on automatically when the the car is started with the remote and it's the same LEDs for regular tail lights and brake lights, just different brightness. If the diode fix fails at any point, I'll give the relay a shot. Thanks everyone. Hopefully this is the end of my problems.

I might draw up a picture in paint later to make sense of what I did.

 

[daboyfrumdabx 10+ year member]

Here's what I did.

View attachment 26521280

Put a diode(black) on the car's brake wire(blue), after the RS wire(brown). The diode is set up to allow current to flow in the direction of the arrow, to the rest of the car only. So any current trying to back feed can't reach the wire to the RS. The RS will still get the signal when the brake is actually pressed to shut down. I just had it run the full 12 minutes that it's set up for and it made it with no issues.

 

[DMP 10+ year member]

Good to hear you figured it out. I dont think you will have a problem with a diode going bad.

 

[daboyfrumdabx 10+ year member]

Good to hear you figured it out. I dont think you will have a problem with a diode going bad.

Thanks again for the help.