Electric brake controller disabled Highlander safety system

[Josh68]

Byron, I'm not sure I get your comment. Are you by chance referring to something like this statement I noticed in another forum?

A caveat to this [diode] mod is you may prevent the brake lights from coming on.

I think this means that in the case of using the manual override, the brake lights might not come on, but I'm just confused at this point. My main concern is that brake lights come on when using the brake pedal and no manual override, but using the override doesn't throw errors or, more importantly, damage the car in any way.

[Raz]

The diode mod should not effect the pedal activation of the brake lights, just the manual over ride on the controller. Interesting, the brake lights on my 2017 Frontier do come on when I engage the manual over ride, so clearly this issue is model specific. Perhaps brand specific. Just curious, does your Highlander have collision avoidance features?.

[Josh68]

Originally Posted by Raz

The diode mod should not effect the pedal activation of the brake lights, just the manual over ride on the controller. Interesting, the brake lights on my 2017 Frontier do come on when I engage the manual over ride, so clearly this issue is model specific. Perhaps brand specific.

Thanks, Raz. I was under the impression that yes, this issue is specific to certain Toyotas with a Tekonsha controller. I didn't really understand this until after I got a P2 (still uninstalled). I think I'll look for the Tekonsha pigtail with diode, assuming it will handle the issue as Tekonsha intends. May be easier and even cheaper than finding the correct diode.

[Raz]

Find a local Ham who tinkers. See if he has a 1n4001 in his junk box. That's what I would use. Install with the cathode (banded end) closest to the prodigy.

[Josh68]

Originally Posted by Raz

Find a local Ham who tinkers. See if he has a 1n4001 in his junk box. That's what I would use. Install with the cathode (banded end) closest to the prodigy.

Thanks, Raz. I'll check that out.

[Raz]

If you can't find something local, send me a PM with an address and I'll pop a couple in the mail to you.

[Josh68]

Originally Posted by Raz

If you can't find something local, send me a PM with an address and I'll pop a couple in the mail to you.

Mighty kind of you. I do know a radio "nerd," so he may be able to help me out. Out of curiosity, would any of the similar, through-hole axial 50V diodes (rated 1 -10A) work? https://en.wikipedia.org/wiki/1N400x...purpose_diodes

[Lynn Eberhardt]

Lynn, on your point about running 3-wire cord, I have a follow-up question.


The HiHy has this auxiliary jump terminal box in the engine. So if I don't want to deal with the extra expense and hassle of running wires to power the brake controller from the battery itself (all the way on the other side of the car, unlike in most cars), would it be possible (and safe) to try using those terminals to provide and battery +/- to the P2, or is that unwise?


If I did that, I'd only need a small amount of cable in the engine bay, a very short run from the battery positive to the 7-pin (both in the rear), and all I'd need to run the length of the car would be the brake controller output to the 7-pin (I could use the bulk of the existing duplex I got with my eTrailer ETBC7 kit for that).

If this is a bad idea, I'll be looking for triplex wire or trying to add an extra length of 10- or 12-gauge to the duplex I have from the kit.

Answer:

I used a 25' extension cord with the ends cut off for my back to front wire under the trim. They all have a black, white, and green wire.

I knew I needed a return from the controller to the seven pin. I knew the brake signal at the T-One connector in the rear would be the least likely to confuse the car's complex electronics - I probably went overboard with an isolation relay when a diode would do. I wanted to power the controller without drilling holes in the firewall. One relatively cheap extension cord: black wire=power; green wire=signal; white wire=controller to seven pin. I used a chassis ground up front for the the controller negative. Trailer brake lights don't come on with manual control lever, but all else works well.

While you're in there playing with wires, I would suggest a voltage sensing relay between your car battery and the trailer seven pin. That way you won't drain your car battery when you are parked but still plugged in. It costs more than a piece of wire but is easy to install and can save much grief.

[Raz]

Yes, the 400x series increases max. PIV ( Maximum reverse voltage) with a higher number. Since this is automotive, anything with a max. reverse of say 15 volts will work. I think the 4001 is rated 50v. If things don't work out, let me know.

[Josh68]

Originally Posted by Lynn Eberhardt

I used a 25' extension cord with the ends cut off for my back to front wire under the trim. They all have a black, white, and green wire.

I knew I needed a return from the controller to the seven pin. I knew the brake signal at the T-One connector in the rear would be the least likely to confuse the car's complex electronics - I probably went overboard with an isolation relay when a diode would do. I wanted to power the controller without drilling holes in the firewall. One relatively cheap extension cord: black wire=power; green wire=signal; white wire=controller to seven pin. I used a chassis ground up front for the the controller negative. Trailer brake lights don't come on with manual control lever, but all else works well.

While you're in there playing with wires, I would suggest a voltage sensing relay between your car battery and the trailer seven pin. That way you won't drain your car battery when you are parked but still plugged in. It costs more than a piece of wire but is easy to install and can save much grief.

Thanks, Lynn

OK, so you did go all interior wiring, it sounds like. Interesting difference is that my t-one is under the dash, not in the back, so I think my red wire will from the controller pigtail will splice in right there.

I appreciate the detail and the suggestion about the voltage sensing relay. I'll look for one of those, as well.

[Josh68]

Originally Posted by Raz

Yes, the 400x series increases max. PIV ( Maximum reverse voltage) with a higher number. Since this is automotive, anything with a max. reverse of say 15 volts will work. I think the 4001 is rated 50v. If things don't work out, let me know.

Thanks for the extra detail, Raz. Yes, the series I was looking at is all 50v, as you suggest (with the 4001 at 50V/1A), just noting that there are models with different amperage ratings.

[Byron Kinnaman]

Originally Posted by Josh68

Byron, I'm not sure I get your comment. Are you by chance referring to something like this statement I noticed in another forum?


I think this means that in the case of using the manual override, the brake lights might not come on, but I'm just confused at this point. My main concern is that brake lights come on when using the brake pedal and no manual override, but using the override doesn't throw errors or, more importantly, damage the car in any way.

The comment concerns OREGON LAW. "If you have trailer brakes they MUST be operational when towing."

I don't know how to make it any clearer.

[gordon2]

Originally Posted by Byron Kinnaman

The comment concerns OREGON LAW. "If you have trailer brakes they MUST be operational when towing."

I don't know how to make it any clearer.

I don't care what the law is... when I come thorough Oregon my brakes will only be operational when I need to slow down. They would burn up in no time if they were operational when towing



EDIT: FYI, The above is an attempt at humor.

[Lynn Eberhardt]

Originally Posted by Josh68

Thanks, Lynn

OK, so you did go all interior wiring, it sounds like. Interesting difference is that my t-one is under the dash, not in the back, so I think my red wire will from the controller pigtail will splice in right there.

I appreciate the detail and the suggestion about the voltage sensing relay. I'll look for one of those, as well.

Yes, my 2017 HiHy has the T-One connector in the back. Up front is probably easier for wiring a brake controller. Toyota certainly makes trailer wiring a challenge with their hybrids.

[Glenn Baglo]

Originally Posted by gordon2

I don't care what the law is... when I come thorough Oregon my brakes will only be operational when I need to slow down. They would burn up in no time if they were operational when towing

operational: in or ready for use: the new laboratory is fully operational.

[Lynn Eberhardt]

The new normal: Silly arguments while social distancing.

[Josh68]

Originally Posted by Byron Kinnaman

The comment concerns OREGON LAW. "If you have trailer brakes they MUST be operational when towing."

I don't know how to make it any clearer.

My goal in this entire discussion is to make my future trailer's brakes functional. I hope that's clear. I just want to make sure I wire everything up in the best way possible.

[Josh68]

Originally Posted by Lynn Eberhardt

While you're in there playing with wires, I would suggest a voltage sensing relay between your car battery and the trailer seven pin. That way you won't drain your car battery when you are parked but still plugged in. It costs more than a piece of wire but is easy to install and can save much grief.

Hello, Lynn

Would this part, or similar, fit the bill for isolating my trailer battery and preventing drain?: https://www.napaonline.com/en/p/UBP8...ttery+isolator

Also, I think I'm about ready to go once I get a hold of a diode (I confirmed with Tekonsha that 1A will do the trick). But I wanted to note that I contacted eTrailer about a HiHy installation with the ETBC7 kit, and they recommended -- insisted, really -- that it's the right way to go to use the auxiliary jump terminals in the engine bay to power the brake controller, and not to run from the battery itself.

On the plus side, this means the 10-gauge duplex I have in my kit should be all I need (providing brake controller signal to the 7-pin, and for the main 12v I can go directly from the actual battery to the 7-pin). On the downside, I think it means I'm going to follow usual instructions and go underneath the car, and also go through the firewall to feed the controller, maybe where the hood release goes through.

[Lynn Eberhardt]

Would this part, or similar, fit the bill for isolating my trailer battery and preventing drain?: https://www.napaonline.com/en/p/UBP8...ttery+isolator

This is the type of relay I suggested:

https://www.amazon.com/Voltage-Sensi.../dp/B07GRM3MMX

Yes, it costs twice as much but is much easier to install. It just goes inline between your car battery and the 7 pin. As for the rest of your wiring, whichever way you're more comfortable with is the way to go.

[Josh68]

Originally Posted by Lynn Eberhardt

This is the type of relay I suggested:

https://www.amazon.com/Voltage-Sensi.../dp/B07GRM3MMX

Yes, it costs twice as much but is much easier to install. It just goes inline between your car battery and the 7 pin. As for the rest of your wiring, whichever way you're more comfortable with is the way to go.

Thanks again for the tips, Lynn. Much appreciated