There are some other threads dealing with installation of a trailer brake controller, but I thought I would post some notes on my installation of the Redarc Tow Pro Elite controller in my 2021 Passport. I like this controller because it has a remote electronics unit that can be hidden under the dash. The user control consists of only a small knob that can be mounted in a switch blank to the left of the steering wheel.
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This is not a difficult installation if you’re accustomed to working under the dash of a modern car. But it’s not for those with claustrophobia. I was a mechanic for over 20 years (in my younger days), so it didn’t give me any particular problems. I’ll try to avoid repeating information you can find in other threads on this forum. I also found very good information in the Honda Pilot forum at
www.piloteers.org.
I recommend buying the controller with the plug and play cable (TPH-013) available from Redarc. This allows you to plug the unit right into the Honda wiring harness. When I bought my controller, Redarc did not list the Passport, but the cable that they listed for the Pilot and Ridgeline is correct for the Passport. You could also make a cable using the pigtail supplied in the Honda hitch package and the universal pigtail supplied by Redarc, but in my view the extra $20 or so for the plug and play cable is well worth it.
In another thread, there are excellent pictures that can help you to find the pre-installed plug for the controller. It’s under the dash, to the upper left, above the OBD connector.
To get access to the area under the left side of the dash, I unclipped the lower dash panel. I didn’t disconnect any switches or sensors installed to the panel – I just unclipped the panel and let it hang. To do this, you have to first pry off the smaller panel at the outside end of the dash, using a panel tool or screwdriver. On the larger panel I didn’t use tools. I carefully pulled the panel loose with my fingers starting at the lower left corner and then around the edges. This is also covered in other postings, but I’ll add that it is not necessary to disturb the door weatherstripping to remove the smaller panel.
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I found (as others did also) that the best location for the electronics unit is to attach it to the right-hand side of the big metal bracket for the parking brake pedal. Because the electronics unit contains the accelerometers for proportional control, it is important that the unit be mounted securely such that it cannot move. I found that the metal bracket has a hole that I could use for attachment of the Redarc unit. I attached it using one 5mm bolt with a nylock nut and some washers (a 5mm bolt typically has an 8mm head). The bolt was about 20mm long, and I had to enlarge the mounting slot on the Redarc unit very slightly to accept the 5mm bolt. The unit nestles into the shape of the bracket very nicely. To provide more support and to prevent vibration, I also secured the unit using a nylon wire tie.
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I found that the universal switch blank supplied by Redarc worked fine for installation of the control knob. I had to grind a very small amount of material off from the dash panel in the rectangular opening where the switch blank goes in. This is also covered in other posts. Redarc’s universal blank didn’t fit perfectly but it looks good and it’s in there solid enough. I wrapped some electrical tape around the cylindrical portion of the blank where it passes through the panel. This gave it some additional support to keep it from wiggling in the dash. Another poster had a similar issue and used putty to firm it up.
Please note that the wiring is long enough that you’ll have some excess wire under the dash. I tied this up with wire ties. Watch for clearance issues with the parking brake pedal, and don’t let wires hang loose such that they might fall down below the dash.
After installation, the fuse for the trailer brakes must be installed under the hood, in the secondary fuse box next to the brake master cylinder. There are actually three slots in this panel for trailer-related fuses, and I think the fuses are supplied by Honda in the parts kit for the hitch. I had the Honda dealership install the hitch after I installed the brake controller, so I just let them plug in the fuses.
The Redarc unit calibrates its accelerometers automatically, in normal driving, without a trailer. When you hook up your trailer and you plug in the 7-pin connector at the back of the Passport, the knob should light up, as described in the Redarc documentation. My unit operated exactly as it should.
For me, the most difficult part of the installation was deciding where to mount the electronics unit. I’m thankful for the help I got by reading the postings on this forum and on the Pilot forum.
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