Yaw Rate Sensor

Anyone knows the ins and out of the yaw rate sensor? I'm building a 130 from bottom up and so i bought an ECU kit that it came in. Will i need to get a Hill Descent Switch?

Could be wrong but think yaw is side to side motion.
D2 had two, one in the roof and one in centre console, Iirc that was for the ACE system.

Does it have anything to do with Hill Descend and do i need to purchase a dash switch for it?

lynall said:

Could be wrong but think yaw is side to side motion.
D2 had two, one in the roof and one in centre console, Iirc that was for the ACE system.

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You're not wrong, yaw is side to side motion, like the back end sliding or skidding away, or the steering of a boat, right or left, doesn't matter.
You're also right about some D2s having two accelerometers, one in the roof and the other one low down, probably in the centre console to measure and counteract the sway or roll due to cornering. Normally referred to as ACE, it was Active Cornering Enhancement.

landromy said:

Does it have anything to do with Hill Descend and do i need to purchase a dash switch for it?

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ACE is a totally different system to the Hill Descent Control system, so I can't see a valid reason for you needing to buy a HDC switch, but you can buy one if you want, they're your dollars.

I'm trying to figure out if I need to have any dash switches to correspond to this sensor. I figured that it was something I would turn off or on. If not then what happens if my truck sways left to right? Does this sensor correct and stabilizes the truck and by what measure?....thanks for all the help

I'm having difficulty trying to work out which sensor you're going on about.
You say you're building a 130, I presume that's a Defender. If that's the case, then I didn't think that the Defender was ever fitted with ACE, but I'm sure somebody will say if I'm wrong.
If it is ACE or Active Cornering Enhancement you are talking about then you don't just "switch off that sensor", it's working all the time. The basic way it works is that there are two accelerometers, one high up in the roof and the other down low in the vehicle. When the vehicle is cornering, centrifugal forces tend to make the vehicle lean outwards from the corner, "body roll". To counteract this roll the ACE ECU will detect the difference between the two accelerometers and allow the hydraulic anti-roll bars to inflate or deflate as is appropriate to force the vehicle to ride flat through a corner.
So, if you haven't got hydraulic active anti-roll bars and an ACE electronic control unit, then you don't need the accelerometers.
If however you're talking about the HDC or Hill Descent Control system, then this is an automatic braking system which is driver selected, that is it has a switch on the dashboard to enable it. It works as a part of the ABS (Anti-lock Braking System) and is used to descend very steep usually off-road hills. When switched on, it allows the vehicle to drive down the hill, automatically applying the brakes to the wheels individually to prevent them skidding whilst maintaining a suitable slow speed without the driver taking any other action that steering. The driver then switches it off again when safe level ground is reached.
As has already been said, these are totally separate systems.
A part number for the "ECU kit" might help us.

Oh wow....i'm reading your response over and over and i might be convinced that the 130 crew cab i bought from foley's is equipped with this roof sensor. There is a space size about 2" x 2 &1/2" right side rear of the cabin that I have been told is for a sensor.
So here it is. 130 chassis from richards; 130 chassis loom, crew cab and rear tub bought from Foley's; Motor and transmission bought used from Canadian builder ; ECU, seat electrics/fuse box, yaw rate sensor bought from another breaker as a set from a broken 2015 130; Main loom and other parts from yet another breaker; Axles abs equipped bought yes from another breaker.
I have been painstakingly putting this together as I go along. No real major bumps until now. After reading your response I cannot determine if in fact I need to look into ACE. The question that keeps popping in my head-Is the 2015 on defender 130 equipped with ACE. If it is not then what is the yaw rate sensor (that was purchased with ECU from breaker-broken 2015 130 ) and opening in my ceiling for?

Thanks so very much-very enlightening

I've done some more research and found out that the roof sensor may be an alarm sensor and the supposed yaw rate sensor may be an ESP sensor. These two make more sense for a 2015 defender 130

Even further research has led me to a DSC ....Dynamic Stability Control. All 2015 model Defenders should be equipped with it......That's the switch that I need

Thanks