So, just to state this up front: I managed to tow our Jeep a few miles with the steering wheel locked completely to one side. Completely noob-ish mistake. But before we get there, here’s the scoop on the final part of the installation:
Setting the stage
At this point, the tow bar itself is installed, the signaling lights are installed, and the baseplate is bolted on the Jeep. The last part is installing the actual brake controller itself, the Roadmaster Invisibrake. Opening the box, there are a heap of parts: The main box, a pneumatic cylinder, wires, tubes, connectors – a bunch of stuff.
Like many installations, this one will really work out better if you ‘dry fit’ everything before you start cutting and crimping.
First, I needed to place the brake controller itself. I had thought it would just fit under the driver’s seat, as I’ve seen it pictured elsewhere. Unfortunately, Little Red (Our ’99 TJ) didn’t have quite enough space under the seat without cutting something somewhere, so I opted to relocate it – in the passenger footwell, but I needed to get the other stuff attached to it to know exactly where. Essentially, I decided to put it there, but left it loose for a final fitting.
Next, I found a place for the pneumatic cylinder. This thing gets air pressure from the main box through an included plastic tube, and pulls on a cable which applies the brakes. So, it needed to be at the right position to get the cable to pull the brake down without pinching the cable itself. The cable cannot be cut, so there is no adjusting that. I put the cylinder between the driver’s seat and the outer wall, on the floorpan, under the carpet. The cables fit well enough (no pinches!). The tube from the main box was connected with plenty of slack. (again, no cutting yet, just connecting things to make sure they will work where I have them.
Then, I had to run some more tubes out to the brake vacuum booster in the engine compartment. This wasn’t too bad – there is a through-firewall grommet that I cut a slit in and fed the tube from the booster back to the controller. The kit comes with a few sizes, and the smaller one worked for me. This thing is needed because the Jeep brakes are boosted by the engine when it’s running. The invisibrake fills in for the engine when towing, so there is no loss in braking power.
Next, I ran the power cables directly from the battery back through the through-firewall grommet, and to the controller.
Another set of wires was from the brake controller to the four-wire connector I ran in part II back to the brake lights. This is actually what signals the controller to activate the brakes – the brake lights on the RV coming on.
The last piece of the dry fitting, was to locate a wire that was energized/powered/hot when the brakes are pushed (usually the wire that lights up the brake lights in the back when the brakes are used normally) and run a provided wire from that to the baseplate near the front bumper.
In Boomer, I also ran a single wire from the back bumper, along the underside, up through the driver’s compartment to an LED which visually indicates when the Jeep’s brakes are actually engaged. (This comes from the brake lights themselves, not the Invisibrake-provided lamps – the _actual_ jeep brakes) This gives me a bit of peace of mind that its working.
At this point, I ran a test, shown in the video below, to make sure everything worked.
And it did! Huzzah!
The only real remaining thing was to do final placement of the components, and cut the wires/tubes/whatever to length. As a habit, I leave some unnecessary slack in all cut wires, to make sure nothing is /too/ tight, and still gives some wiggle room. The controller is as far up the passenger footwell as it can be, to keep it from being obtrusive (and it isn’t – you can’t really tell its there with the foot well carpeting and mats covering it.)
This was a pain. It wasn’t that it was super difficult, it was that the consequences for getting it wrong are so high (runaway Jeep on a rampage?). I really took my time, and double checked everything. It was absolutely key that I dry fit everything first. I must have re-positioned stuff a dozen times before I got what I was looking for.
Each time we towed, we really wanted to be able to do as little as possible to hook up and go, and this seems to have done it. Its also not visible at all when in the Jeep. I think we accomplished that goal. I might consider having it professionally installed next time, however. I mean – I know its done solidly, and I can trust it, it was just hugely time consuming.
Since this post has been a bit long coming, we’ve actually managed to use the set up a few times. It works completely fine. I can’t really even notice the Jeep on the back all that much. It doesn’t really turn any different, or handle _that_ much different (I can feel speed bumps two more times as the Jeep goes over them, but its really hard to tell).
All-in-all, its a complete win. I would definitely recommend either having this done, or doing it. Its totally worth it! Towing a Jeep has expanded our range at the destinations greatly.
After all the flowers and sunshine, I should probably mention, as reminded by Sonya, that our first (short) towing trip was a bit of a learning experience:
We went about 5-10 miles away to a very close campground (sandbridge beach resort) and used that to test the set up. I had read that the Jeep TJs didn’t need to have their steering wheel unlocked. Well, whoever wrote that is a knucklehead. And, I’m a bit of a dummerasel for believing what I read on the Internet. Turns out, TJs _do_ actually need to have it unlocked. So, we drove the few miles there with this really odd whining noise which we couldn’t identify. It was one of the wheels (which was out of alignment) not pointing in the same direction the Jeep was going. And, the RV is powerful enough to just keep pulling it.
No harm was done to either Jeep or RV, (though we did get an alignment on the Jeep just to be sure) and we learned our lessons: a) The Internet LIES! and b) TJs do, in fact, need to have their steering wheels unlocked for flat-towing. 🙂