Haptic Motor Failure

[cslynch]

Hi all. I recently bought a 2015 Yukon XL. I bought it knowing that the "Service: Driver Assist System" error was showing and I understand that this is a very common issue. I replaced the wiring on the haptic motor as detailed in the following video: 

 

I have tested the motor by applying 12v leads from a battery into the plastic connector. The motor and wiring are both doing their job when power is coming directly from the battery. Also, the dash is no longer showing the "Service: Driver Assist System" alert. 

Unfortunately, when I cross the center line on the road, the Lane Departure indicator light changes from green to amber and flashes, but the motor doesn't actuate. I tested the leads on the motor and see 0v being applied to the motor on the left side of the seat. The right side motor works fine.

User gary41 indicates at the bottom of this post (I understand this is Cadillac, but I assume all GM haptic feedback design is generally the same) that a non-operating haptic motor can cause damage to the seat control module: http://www.cadillacforums.com/forums/cadillac-forum/t-730154.html

Am I headed in the right direction? And how can I test this?

 

 

[Justin101714]

Well, I think you would need to be sure the module is commanding the motor on. You’d need an output function on the scan tool to command it manually. These haptic motor wires also break within the insulation and don’t show evidence of a failure. Just because you put 12v on them, don’t assume the wiring is good. Manipulate the small harness around while turning the motor on with an outside source of power and ground. I find it strange that the message is no longer showing in the DIC though. The circuit from the haptic motor on the body side of the harness could have damage as well. Inspect the harness under the seat to be sure no portion of the harness was snagged my a linkage or rubbed through by a bracket or motor.


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[cslynch]

Thanks a lot for the reply Justin. I actually know the wiring is good because I pulled the motor from the seat and replaced the 24G wire with 20G. I soldered the new wiring directly to the leads inside the motor housing and then tested by attaching +/- from the plastic linkage to the battery while the motor was out of the seat. I'm pretty confident in everything up to this point.

 

And I THINK I have confirmed that the module is not commanding the motor to come on. I don't have access to a scan tool. Instead, I backed up to a wall so both haptic motors should be actuated. The right motor gets triggered as you would expect. And it works. The left motor gives every indication via the screen/dash lights that it should be actuating. When I put a meter on the +/- leads on the haptic motor (motor is still outside of the seat, by the way...just plugged in to the linkage and sitting on the floor behind the driver's seat) I see 0V. It is not being triggered by the control module.

 

I think. 

 

What module sends power to the haptic motor? Where is it located? And can it be damaged if the haptic motor isn't connected to it for an extended period of time? I know I can trace the wires back to the module. But I'd rather not take the seat out to trace everything back if I can avoid that amount of work.

 

What's my next step?! And thanks again for the help.

[Justin101714]

I would at least go back from each connection at the haptic motor connector and the seat memory control module at least 6 inches. The seat memory control module commands the haptic motors on. The module is underneath the drivers seat. It has 5 or 6 connectors going to it. The module will require dealer programming to function. The drivers seat left haptic motor coming out of the module is on connector X5 terminal 5, yellow/brown wire. The connector is Black.







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[cslynch]

You are the man. Thanks a lot Justin. Have you seen that module go bad when the haptic motor wiring breaks? Like I said, I only found one post on the internet that suggested that as a solution. I just don't know where else to look.

[Justin101714]

The module won’t go bad because the haptic motor or wiring is bad.


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[tbarn]

From my experience ( about 25 - 30 ) haptic seat/ Service Driver Assist , 100% have been haptic motors.

[Justin101714]

You need to be super sure your wiring from the seat memory control module to the connector for the haptic motor is good. I would suspect that before I would replace a module. At least get your meter and be sure the circuits end to end from the module to the motor have some continuity, make sure the control circuit isn’t shorted to ground or open. The meter should show “OL” when on the ohms scale on the control circuit and one lead going to chassis ground. If it shows “OL” from end to end, you need to keep digging and find the open or just restring the circuit.


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