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I want to make my radar detector vibrate my seat

4K views 51 replies 8 participants last post by  djdonte 
#1 ·
I have my Escort Max360 hardwired with a smart cord. I sometimes have trouble seeing or hearing the alert between my exhaust and music. The vibrating module in the seat has to be a simple 12v motor. I’m no electrical engineer but I was thinking of a relay set up. I’m guessing the blue LED in the smart cord box is fed around 3v so I would need a relay to give the seat motor 12v from a 3v trigger. Does such a thing exist? Any ideas or input? Am
I crazy? I’m sure there is constant 12v under the seat for the motors. I am comfortable opening the smart cord box and soldering or whatever else I need to do, although I am hoping to tap into the wire between the box and detector for the trigger voltage for the blue alert light.

Here is the smart cord:
Escort Direct Wire SmartCord (Blue Light) https://a.co/d/0NOkLMu
 
Discussion starter · #10 ·
Thanks for the input guys. I want to tap into the seat vibrator, not install a new one. I could run the trigger wire to the seat and have the relay there to feed 12v to the motor, but in a perfect world I would find the corresponding wire in the lower front dash area. Does anyone know where I could find such schematics?
 
Discussion starter · #14 ·
According to a wiring diagram I found in a large FSM online, the BCM communicates with a seat memory control module under the seat thru a serial data connection. So there would be no finding wires near the dash or at the BCM. From there, there are two outputs labeled RR and LR haptic seat motor control. I also found DTCs that mention this haptic motor short to ground AND short to voltage. I am concerned just tapping into one of these wires would throw a short to voltage DTC. With that being said I think I should buy a haptic motor and install it. They are 35-55 bucks online.

Weirdly, this manual claims to be for 14-17 CTS, but also mentions wagon and coupe, so I am a little confused. I have yet to look under my seat but it is pretty tight so I am not sure I will even be able to see anything under the Recaros without removing them. I wanted to at least try to identify these wires and possibly problem then while activating the collision system in the rear.

There are some walk thrus on replacing these in the GM trucks, where the cushion comes up pretty easy without removing the seat. Not sure if its that simple with the recaros. The motors seem to just sit in some void in the foam cushion. I am going to poke around a little bit during the holiday weekend and try to see if I can find any info on removing the seat cover.
 
Discussion starter · #16 ·
The link is ok my work computer and it’s over 200mb but this is the screen shot I have with me.
Wood Rectangle Font Office ruler Grille
 
Discussion starter · #20 ·
Far as I recollect, Seat Vibration was not an option for any V2 at any time, in which case this page has to be V3 specific.

I agree, it looks like they're switching both sides of the vibration motor and I can't for the life of me understand why they would have done it that way. You're probably better off just grabbing the motor linked to, above, and using that dedicated to the radar detector. It's possible to figure out what the BCM is doing with a Volt Meter, but it's more work than it'd be worth to figure out and then design something that could use the motor independent of the BCM.
They aren’t switching both sides of the motor, as there are two motors per seat so I think that’s the hot wire for each motor.
 
Discussion starter · #24 ·
Except the schematic is labeled "in" and "out" not "left" and "right" or "one" and "two". Which is why I supposed they're switching both legs. Either way, though, I think the best approach is a dedicated motor. Tying in to GM electrical systems can be tricky, at least in my experience. Going back to when I tried to hook up the backlights of a gauge set on my 02 Z06 to the dashlight circuit, and I discovered for some reason the dimmer circuit switched the low leg to ground, not the high leg to V+. The dash got dim when the gauges got bright, and vice-a-versa. I had to make a little FET inverter circuit to drive my gauges. Never assumed GM engineers made sensible decisions since then.
The schematic is actually labeled LR and RR so I am confident it is the hot leg of each motor. It just needs to vibrate not change directions like a seat motor would. In any case I have decided against using those wires as I dont feel smart enough to incorporate a diode (I think thats what I would need?) and I dont want to deal with BCM short to voltage DTCs. I dont have a tool that will read/clear those codes, only OBDII. At some point it would be cool to make it plug and play with the existing seat motors. I ordered the relay module and a haptic seat motor from Amazon and plan to tinker with it this weekend. I guess my plan would be to attach the motor to the bottom of the seat if it vibrates enough, or incorporate it in the foam similar to the existing motors.

Cars are indeed more complicated than back in the day. I've hardwired either a radar, dashcam or an FM modulator in every car I've owned. It used to be easy as hell to grab a switched 12v source in the fuse box but these days every damn thing is supplying constant 12v to a module which then decides whether to give power to the window/seat/whatever based on a serial data connection.
 
Discussion starter · #25 ·
Automotive tire Sports equipment Wire Electrical wiring Bicycle handlebar

Here is the guts of the smart cord control box. The "5th" wire is one of the power wires coming from the fuse box so I already know its gets 12V whenever the car is on or has RAP before I open the door after shut down. I probed the wires with a ground to chassis. I was not able to make the detector fire off a real alert, but if you get the smart cord in the right position in the detector, it lights up both LEDs. The blue LED is always on when the detector is powered up, and the orange lights up on alerts. I have a HF meter so the super low mV could be noise:

1. Detector (RD) on: 47.7mv, Alert 0v, RD unplugged (car on) 0
2. RD on: .303v, Alert 2.07v, unplugged 12v
3. RD on 12v, Alert 12v, unplugged 12v
4. RD on 3.2v, Alert 8v, unplugged 0

alerted the part that confuses me. Both LEDs get about 2V when theyre lit, nothing when they arent, and show 12v when the detector is unplugged but dont light up. Also, I started testing resistance between chassis and the wires and they were all over the place except wire 1 which was 297kohms when on, and 7.7ohms when alterted. I'm no EE... anyone have any insight? This is what I ordered and sounds like in low mode it will fire on 1.5v. Not sure about high. The front of the seat comes apart easy and there shouldnt be a problem getting the haptic motor in there.

Amazon.com: HiLetgo 12V 1 Channel Relay Module With Optocoupler Isolation Support High or Low Level Trigger : Industrial & Scientific
 
Discussion starter · #26 ·
Also I found this:

 
Discussion starter · #28 ·
The reason why you get 12 volts on the LED when OFF and 2.7 when ON is the circuit opens the GROUND path to the LED.

Connect the negative lead from whatever you are using to trigger (solid state relay) to the point that goes to ZERO (#1) and the POSITIVE of the trigger to #3 (maybe #4)

Most of these cars switch GROUND and not POWER in the mirror circuitry.
Thanks for the insight. I grounded the meter on 1. #3 was 12v anytime the RD was on, alert or not. #4 was 3v when the RD is on, 7v on an alert. So I guess I need a relay to trigger on more than 3 but less than 7ish volts? The relay I ordered has a hi and lo setting. The low triggers on 1.2-1.5 according to the reviews but I’m not sure on the high setting.
 
Discussion starter · #31 ·
I would use a potentiometer and "dial it in" if I needed to.
Use the "high" range setting on the trigger and your should be good to go.
So I got everything hooked up with jumpers to test and the relay runs the haptic motor no problem but unfortunately even in high mode the 3v triggers it all the time. I have an assortment of pots and resisters on the way. Any idea which pot I should try first?
 
Discussion starter · #32 ·
Got it all figured out. I tried a 100K pot and the relay pretty much triggered at 1.2V on hi limit setting. So with the RD on, I used to pot to dial back the 3v idle voltage until it got just under 1.2V. This way the relay only triggers on an alert.

Looking at my picture above, I tapped into the yellow wire for the alert. This sits at 3v during normal operation and spikes to 8v on an alert to trigger the transistor to ground the alert LED. I was able to do this down the line with a t-tap so I did not have to solder on the small control board. I wanted to remove the seat but it was really cumbersome and my back wasnt liking it, so I just removed the rear bolts and unlatched the front so I could slide the whole assembly forward. The seat bolts were large (T-50?) and had blue locktite so they were kind of a bear to break lose. I did add more blue thread locker when replacing. The negative battery terminal was removed before disconnecting the main seat harness as it has SRS components in it, but in hindsight, since I was not removing the seat I could have left that connector intact and just removed the negative battery terminal.

To remove the seat cover, I had to remove the front seat panel which was just held in with clips, and the outboard seat panel, held in place by T-20 bolts front and rear. There is a connector for the seat controls, and after that is gone, the seat cover is held in place by a metal bar also with two T-20 bolts. This is the only part that would be very hard to do with the seat not moved forward off its mounting point. Once the bar is gone the cover is held by j clips on the side and front. I was able to peel back the cover maybe 1/3 to 1/2 way. The foam in the side bolster was torn and dry rotted, so I added some foam I had laying around as it was hard to not tear it more when replacing the cover. It seems the adjustable bolsters are not kind to the foam. I am not so sure the cover is supposed to be separated from the foam, as there are clips that tear away from the foam when doing this. It is also held down in channels with velcro. I used my fingers to tear out a cavity for the motor a little forward of the existing haptic motor and stuffed it in there.

I ran the leads down the front of the seat and under the carpet to the edge of the car then up under the dash. I've never seen car carpet with so much padding. I am guessing this is cut down on noise. It also explains why it is so tough to get good exhaust sound out of these cars I think. Moving the seat back off its mounting points was also required to hide the wire under the carpet. I tried several different fishing techniques with the seat bolted in and no dice. The insulation further complicated things.

It was very tricky to get the seat cover back on properly. Just stretching it over the bolster pulls foam down with it and you end up with a weird looking seat with hard spots. I had to keep making sure to keep the bolster tucked in as I pulled the cover over. After that I replaced the seat trim, bolted the seat back down, cleaned up the motor wires a bit, and reinstalled the rocker panel trim where the carpet meets the car body. Wiring everything up wasnt bad, I did it all under the kick panel above the pedals. Right now the relay and pot are just a mess of wires insulated with electrical tape, but I will have a small enclosure for the set up installed soon. I pulled off of the power wire for the RD, so it is fused with a 5 amp fuse which I think will be plenty sufficient, but I considered ordering another tap to take power from another branch. The relay itself only pulls a few mA and the motor cant pull very much either. This is pulled off of the wireless charger fuse location, as this is one of the few circuits with switched power. It wouldnt kill me if it blew since I dont really use that cubby hole for charging.

I would also like to use resistors instead of an adjustable pot but I am not good enough with electrical theory to figure that one out, so I will likely leave the pot, and secure it either to my enclosure or the kick panel. This would also allow for a disconnect for the motor since turning the pot all the way down will stop the relay from being triggered no matter what. The seat harness is right at the front under the seat so it would be cool to tap into the existing haptic motor with a diode to prevent confusing the seat module, but I am too scared to do that without a scan tool that can clear those DTCs.

If anyone wants part numbers or has more questions let me know. I am not sure how different this would be on the non Recaro seats but would guess without the adjustable seat bolsters it may be easier.
 
Discussion starter · #34 ·
Well screw me... The trigger wire gave off 8v when I wiggled the cord to make all the lights go off, but on alert during regular use it does not rise above 3. I drove it around and got some K band alerts and nothing. Ugh. I can make the detector go off for laser with my phone but it take a min to get it to work.

I ended up opening the box back up, soldering a wire to the + side of the LED. Now I have 2ish volts on alert, no voltage on idle, BUT on start up it gets 12v and also gets 12v if I unplug the RD while the car is on. Not sure what I am going to do, besides wire a switch to the trigger wire to control it. Its pretty annoying. The motor vibrates for 2-3 seconds on start up, and also if I disconnect the RD when stowing it, if I do so before opening the door to cut off RAP.

I wonder if there is a switched circuit that does not get RAP? If so I could power the relay with that, this way it wouldnt work no matter what comes thru the trigger wire.
 
Discussion starter · #36 ·
I’ll try that. The relay power supply needs to have common ground with the trigger. So I’m guessing both grounds goto negative LED, positive trigger to #4, positive relay supply to 12v accessory power?
 
Discussion starter · #38 ·
I think we are confusing each other. Go look at the Amazon listing. The relay itself needs 12v supply to function, completely separate from the 12v being switched to the motor. I believe according to the specs, the trigger and supply ground need to be common.
 
Discussion starter · #40 ·
Thanks that worked like a charm. I soldered leads to each side of alert led on back of the circuit board. Here is a rough sketch of my relay and how I did it. This relay needs a 12v supply to function. I was not sure sub 2v would fire the 3vdc relay. This only gives the motor 12v when the alert LED fires, not when the RD is unhooked or any other time. I got rid of the potentiometer too.
Font Rectangle Circuit component Electric blue Audio equipment
 
Discussion starter · #42 ·
Damn ok.. That is pretty much what I've been looking for. I am going to order the DC to DC 25A version of that SSR you referenced? Will I need to utilize the heat sink for such a low load?
 
Discussion starter · #43 ·
Some of the reviews are saying this thing triggers at 3v. The led only puts out about 2v. I guess I'm trying to understand the risk of "blowing shit up" with my coil driven relay? I'm going to try the SSR either way.
 
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