| Dick at Incline |
| I just got my MDX a week ago and had the Trailer towing package installed. Now, how do I install a 7-Pin connector so I can operate my Electric Trailer Brakes. Jeep and Ford have Extra wires, front-to-back to simplify installation. Looks like with the MDX, you have to run wires under the carpet yourself--not very well thought out--Me Thinks. |
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| catzx6 |
| I just swapped my 4-flat for a 5-flat. The wire for the back up lights is at the body plug where the trailer harness plugs into it. I had to splice the new plug into the harness, but I only needed the back up light power for the reverse lockout since I have surge brakes. I have the electrical T/S manual, so let me know what you need to draw power from for the electric brakes. I'll check the manual and see what I can find. Good luck :rolleyes: |
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| Dick at Incline |
| Thanks for your help. My trailer has Electric Brakes, so I have to use an electric brake controller. The controller requires +12V, Ground, and a signal from the Car's Brake switch that Brakes have been applied. The dealer told me that I can get the signal from the White/Black stripe, wire from the switch near the Brake Pedal. The controller outputs a DC Voltage (Voltage level determined by the controller, depending on the amount that the Electric Brakes need to be activated). So my main interest is in getting an extra wire back to the connector (this is a 7-pin round connector not a 4 or 5-pin flat connector) to activate the Electric Trailer Brakes. Most Vehicles that can be used for Towing have this spare wire available, but I think the MDX does not. |
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| TheWorm |
How much juice (amps, from 12V+) do the brakes require? Easiest grab would be the accessory socket back there, left rear quarter (20A), and there's nothing else drawing power from that circuit (at least not on the 01/02). The rear trim (tailgate area) is easy to pull off; you can probably fish a wire from the socket, through the jack storage area, then down under (or through) the rear storage bin to where the rest of the harness is hooked up.
Worst case is you'll have to pull that quarter panel trim piece where the socket is located (ask someone w/an 03 service manual for instructions -- it's not just a pop-off like the others). Not too long a wire run, tho.
Or are you primarily concerned w/getting the BRAKE signal? Wouldn't that already be included in the existing connector that activates the brakelights themselves? (or does the switch need to know your braking force?).
Good luck. |
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| Dick at Incline |
| The +12V goes to an Aftermarket Brake controller that is mounted near the driver. That controller is adjustable based on Trailer Load. Then the controller outputs between +1V and +12V depending on how hard you are braking the car. So I can't just take 12V from the Power source in the back, because I need to take a variable voltage from the controller to the brakes, that's why a separate wire is needed. With all the Wires in the MDX, I'm surprised they make it so difficult to hook up a trailer with Electric Brakes. This is especially odd since on page 278 of the Owner's Manual they say "Electric Brakes mus be Electronically actuated". Then they say, "See your brake manufacturer for more information on installing electric brakes" But that just, "Begs the question", because wires are needed in the MDX to control the Electric Brakes. They are available on Jeep, Explorer, Dodge, Ford Trucks, but not on the MDX!! A major inconvenience after I just spent $850 to have a trailer towing package installed, and I still must spend more to install Electric Brake control, which should be a Plug-and-play, like other SUVs. |
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| TheWorm |
I could be totally lost...so you need a VARIABLE INPUT for the controller? Based on pedal position, I presume?
Well, how 'bout some more (potentially) bad news, then? Keep in mind that I don't have a trailer and have never towed anything, nor do I understand the mechanics/hydraulics of brakes.
But, based on the 01/02 service manual, it doesn't appear to me that the white/blk wire on the brake pedal position switch is gonna do you much good. It looks like it's a basic on/off and doesn't measure anything in between. It'll have 0 volts *or* 12. 2 choices. At least that's the way I'm reading it. The 03 could very well be different, given the VSA system. You could check w/a multimeter to see if it's 0/12 or 0-12 based on position.
If it's bad news, I imagine there's an aftermarket switch from the trailer mfr that could be attached to the brake pedal that measures intended pressure based on the pedal travel, right?
You might want to ask your dealer for a peek at the service manual to check the schematics, etc, unless someone here with an 03 manual checks in. Or someone who's done a trailer w/electric brakes. Have you done a SEARCH for that?
SEARCH for "electric and brakes" without the quotes. You might have to PM or email some of the folks who indicate they have electric brakes to find out what gear they're using and how it's set up, as I didn't see any detailed solutions in my brief scan of the threads. |
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| Dick at Incline |
| Here's a quick Run-down on how the Electric Brakes on the trailer are controlled. First you must buy a Brake controller from a company like Tekonsha. This controller is what develops the variable voltage (+1 to +12V) to activate the Trailer's electric brakes. There are three input wires to the controller and one output wire (which goes to the trailer brakes). The input wires are +12V, Ground, and a connection to the MDX brake light wire, which can be connected near the brake pedal. Now the trick is that the Tekonsha Brake controller has an inertial sensor built in, and this sensor determines how fast you are stopping the MDX. Then the Brake controller outputs a voltage, on the "output wire" that is proportional to the amount of braking you need on the trailer, to match the braking on the MDX. So if you are braking the MDX (as indicated by 12V being present on the MDX brake wire) then the controller puts out maybe +1.3 volts if you're braking slowly, and if you are braking pretty hard, then the inertial sensor determines this and puts out maybe +4.7volts. If you slam on the Brakes then the controller puts out maybe 10 to 12 volts. |
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| shootist |
If there is no manual sensitivity adjustment, can't the trailer brake controller be mounted in the rear? If so, the logical solution would be to supply a +12V signal from the rear brake light. This rear brake light signal is available at the trailer connection harness in the very rear of the vehicle. (it's hidden by the rear-most plastic cover in the headrest storage, which pops off).
The higher-amp +12 v to power the brakes would then be a short run from the rear power tap. |
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| Dick at Incline |
| Yup there is a manual sensitivity adjustment on the controller, that you set depending on how much weight you're carrying in your trailer. You set it by driving the car about 25mph, and press the brakes hard. If the trailer brakes lock, then you reduce the sensitivity and try again. If the car does most of the Braking then you set the sensitivity higher and try again. It takes 3-4 tries to get it right. Also, trailer brakes take about 12Amps, so they install a 25amp, self re-setting breaker a wire that comes from a high amp feed from the battery. I'm just disappointed that after paying $850 for a trailer towing package, I must now pay $100-125 to get the 7-pin Electric brake connector installed, most of which is labor to pull the wires that are needed. Especially since other SUV manufacturers install this connector as a part of their "Trailer Towing Package", which typically costs $350. Anyway, thanks a lot for all your help and suggestions. I asked the Acura dealer to install this, but they can't do it. They said, "Take it to a Trailer Dealer" |
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| ostrowc |
quote:
Originally posted by Dick at Incline
Yup there is a manual sensitivity adjustment on the controller, that you set depending on how much weight you're carrying in your trailer. You set it by driving the car about 25mph, and press the brakes hard. If the trailer brakes lock, then you reduce the sensitivity and try again. If the car does most of the Braking then you set the sensitivity higher and try again. It takes 3-4 tries to get it right. Also, trailer brakes take about 12Amps, so they install a 25amp, self re-setting breaker a wire that comes from a high amp feed from the battery. I'm just disappointed that after paying $850 for a trailer towing package, I must now pay $100-125 to get the 7-pin Electric brake connector installed, most of which is labor to pull the wires that are needed. Especially since other SUV manufacturers install this connector as a part of their "Trailer Towing Package", which typically costs $350. Anyway, thanks a lot for all your help and suggestions. I asked the Acura dealer to install this, but they can't do it. They said, "Take it to a Trailer Dealer"
That's what I was about the sugest, that most of the boosters that I have used in the past were maunally adjusted (depending on what you tow. The I/P voltage is constant at 12V but depending on the load O/P from the booster to the brake is adjusted. |
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| TheWorm |
Thanks for the education. Sounds like the install will be relatively easy, at least. Just a thought, that shootist mentioned, is that if you don't need continual/frequent arms-reach access to the sensitivity adjustment -- and if you can use a 20A fused circuit instead of a resettable breaker direct to the battery, then the cleanest install and shortest wiring run will be to use the wiring on the vehicle-side of the trailer harness (under rear hatch panel, near storage bin) for brake signal and then the rear accessory power socket for power (ground is right behind it). You could mount the controller in the storage bin, in the jack panel area, or under the 3rd row (depending on size).
Of course, that's if you don't mind pulling over and getting out to adjust sensitivity.
That'd be a lot cleaner and less labor-intensive than the battery run, brake switch, then wire run all the way to the back. |
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