Originally posted by BillArf:
About your SMI brake system.. It would be really nice if you could take the time and describe here the install. The BX1126 baseplate install and such I have covered quite well but this thread is lacking info on toad braking. I'm sure many an '07 and '08 Wrangler owner has come here and let with a smile because they gained so much needed info. <span class="ev_code_GREEN">I wish a few of them would return and talk about their Wrangler '07, '08 auxiliary braking system.</span>
OK, finally got the SMI Stay-N-Play Duo brake system installed in my 2008 Wrangler Unlimited Sahara.
Here are some pictures of the completed install:
The break-away switch was installed into an existing hole on the bumper using a 1/4" nylon bushing to space it down from the bumper so it sat parallel to the ground. The two wires enter through a small hole I drilled in the plastic belly pan.
As you can see from the finished install photo, you would hardly know the system is there and only requires a flip of the toggle switch on the kick panel mounted controller. The controller is simply screwed into the plastic kick panel. As per recommendation from Pete at SMI, you should mount the controller on the kick panel slightly tilted towards the front.
I mounted the cylinder on the brake pedal just high enough on the pedal arm so as to not be in the way of my foot. The firewall on the Jeep is alarmingly thin. Rather than use the sheet metal screw supplied by SMI, I used a stainless steel machine screw and large washer and nut on the other side. One point of improvement SMI could make would be beefing up the clamp on the cylinder. Make sure you position the shaft of the Jeep's brake pedal arm all the way forward in the clamp. It will bend when the brakes are applied if you do the opposite.
Pete suggested the position of the under hood unit and there really is no other place for it. I rotated it to the vertical position rather than the horizontal position he recommended. It fits better that way and position does not matter. It is cable tied to the computer unit using the lower two holes on the SMI unit. All the wires and air hose to the cylinder are easily passed into the Jeep through a large punch out in the firewall to the right of the power brake unit. Remember to seal it up with silicone when done.
The main unit has a captive vacuum hose that needs to be T'd into the Jeep's brake vacuum line which you can see to the left of the power brake unit in the photo. Power is run directly to the battery with an inline fuse holder (the tap in the fuse box I'll cover later). Grounding is critical. The instructions warn of this but I took it lightly and had some initial problems. The system connects to your coach 4-wire lighting ground AND a chassis ground. I figured that the cool tech wiring harness I was using for the lights was grounded "somewhere" and all I had to do was splice into the cool tech harness. Ha! -- Started blowing fuses at first test. I later grounded the system and the cool tech harness to the computer unit that the SMI unit was mounted to with spade connectors. You can see these in the side shot of the under hood install.
SMI provides an indicator light that illuminates when the Jeep's brake pedal is depressed. You tap into the cold side of the brake light switch -- the White and Tan wire. Their solution involves a large amber light that you cable tie to your tow bar and monitor with your backup camera. I'll let you formulate your own opinion of that
. Instead I ran the wire to an unused pin on my 6 pin connector at the front of the Jeep. That same pin on the RV's 6 pin connector runs a wire up into the cab of the RV and to an LED I mounted in the dash to the lower right of the driver (see photo).
Now to the big Gotcha. When the SMI unit applies the brakes, the brake pedal in the Jeep is depressed. This turns on the brake lights of the Jeep. Two problems arise from this. One, the Jeep applied brake lights wash out the turn signals coming from the coach and the biggie -- The SMI sees the 12v from the Jeep pedal being pressed and stays on FOREVER. That's right, you step on the brakes once and they never come off! Both of these problems could be avoided by using separate tailight bulbs and not using the Jeep's lighting (sorry Bill
) and is actually what SMI recommends.
There is a solution or two. When I first encountered the problem, I knew exactly what was happening. I had assumed this would happen and even inquired with SMI before purchase what the solution would be. I was incorrectly told that it would not be an issue. I disconnected the brake light switch wire from the Jeep and the problem stopped. The Jeep no longer turned on its brake lights when the pedal was depressed, the SMI did not go into a loop and the turn signals were not washed out. Of course you can't drive around with no brake lights when not towing the Jeep so I first put in a simple toggle switch.
Wanting a slicker solution, I thought about a relay. I'll give you the short version. After many hours of head scratching, sketches and trips to the local auto store, I ended up "designing" an existing product -- the Roadmaster Brake-Lite Relay. It's an automatic switch that connects the brake light switch when power is applied from a circuit that is energized only when the engine is running. Buy the Roadmaster product and install it according to their directions. The photo of the fuse box shows where I tied the power for the relay into. It is an unused circuit labeled Rear Heated Seats. It is off when the Jeep key is in the tow position and on when the Jeep is running. I tied into the cold side of the fuse holder with a fuse tap and installed a 10A fuse.
The install took three days, mostly because I would do something one way then realize a better way and re-do it and the time spent troubleshooting and "designing" the brake light switch relay. Working under the dash in the Jeep is a pain. I mean literally. I have bruises all down my right side. I suggest a well placed pillow on the Jeep door sill -- thought of that only after the first day
I've only tested the system in the driveway at this point. RV is still under a cover and a couple inches of snow. Ready for the spring and the first road test.