Tekonsha ZCI and ADAS lockdown

[rbrak29]

Anyone install a Tekonsha ZCI to get around Rivian's ridiculous ADAS lockdown while a receiver bike rake light (brake and turn signals) is plugged into the 7 pin? Seems pretty straightforward. The 12V from the jumper wires could be used to power the Tekonsha.

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[ndmiller]

Do it and report back.

 

[rbrak29]

Several problems. First, the 12V jumper wires are attached to the battery somehow, but no 12V is detected when Rivian is powered on. So will have to go into the bed or further forward to get 12V. Why Rivian only put 12V in the gear tunnel is beyond me. Could somehow wire a 120 to 12V converter to outlets in the bed. Second all 'hot' pins needed (brake, turn, running) in the 7 pin connector are at 13.5 V while truck is on. Something needs to be plugged into the 7 pin, i.e. a 7 to 4 pin adapter with something attached (a load), to get the pins controlling the turn (brake) signals to drop to 4.35V (goes to 13.5V when lit). So if nothing is plugged into the 7 pin there is no signal (amp/voltage change) for the Tekonsha to trigger off of. So that means going into the tail and brake light wiring harness in the bed.

OK, I get it, Rivian wants to know if you are pulling a trailer. All the Accessory Mode does is not display the trailer behind the Rivian in the center screen. All the ADAS is turned off like you were pulling a trailer.

If all you want to do is power some lights, bike rack lights, crossbar lights, etc, all Rivian would have to do is program (Accessory Mode) a situation that if something is plugged into the 7 pin and going down the road the Rivian detects NO weight being pulled, turn ADAS on, at least some of it...adaptive cruise, blind spot, hands on lane centering. Come on, if my F150 can do it, Rivian certainly can.

 

[JM.]

The ZCI won't work at all on a Rivian. It uses inductive collars to detect current going to the brake/turn/tail lights when they are on. But the Rivian has constant voltage to the lights and uses CAN bus signaling to turn them on and off. There's a logic circuit inside each light. The ZCI would simply sense a constant low power.

The slightest amount of load on the trailer pins will trigger the idiotic ADAS lockout.

Once again, why adding a Comma 3X is a huge value. It will keep working, and does quite well with towing.

Also, what does 12v from the jumper wires mean? What wires are those? You can take the 12v from the trailer plug to power things and it will not trigger the lockout. But any load on the lighting pins does kill ADAS.

 

[rbrak29]

Also, what does 12v from the jumper wires mean? What wires are those? You can take the 12v from the trailer plug to power things and it will not trigger the lockout. But any load on the lighting pins does kill ADAS.

The 12V battery jumper wires behind plug opposite the 7 pin.

 

[JM.]

Oh, gotcha. Well, you can do that or use the 12v from the trailer plug. I've tested it extensively to determine what will or won't trigger the lockout. I tried fooling it using optocouplers which have a basically infinitely tiny load; it still senses it on the lighting wires.

But again, the ZCI is a no-go. I've considered getting a generic CAN decoder with some relays to trigger the trailer lights, which would work.

 

[rbrak29]

Oh, gotcha. Well, you can do that or use the 12v from the trailer plug. I've tested it extensively to determine what will or won't trigger the lockout. I tried fooling it using optocouplers which have a basically infinitely tiny load; it still senses it on the lighting wires.

But again, the ZCI is a no-go. I've considered getting a generic CAN decoder with some relays to trigger the trailer lights, which would work.

The jumpers are not lit, no 12V, when car is on.

Rivian can easily program around this, but choose not to. If other major OEM’s can do this (towing with ADAS)…sometimes I get so frustrated with Rivian‘s timidity I could just scream.

 

[JM.]

I get so frustrated with Rivian‘s timidity I could just scream.

100%. I would not choose Rivian, and don't recommend it, unless you really need a truck and aren't willing to put up with the stupidity of the other EV trucks. We really do need a truck and the others are a joke in some way.

Here is my test rig with the results. Yes means lockout if connected.

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