Thread: Tekonsha P3 brake controller in D90

I had posted this in the What did you do in your Landy today thread, but thought I would put it in here as when I was looking for info on doing this, there was only generalised info given.





Bear in mind this is the way I did it, others may know a better way but I couldn't find them.

I split the battery cables (black and white) into 1 x 10mm corrugated split tube, I actually used single 6mm wires for this side not dual core as I also ran a blue 3mm wire for a later project while I was at it.

The blue (brake cable) and red (stoplight cable) I used dual core for this. I first of all soldered and double heat shrunk all of my 6mm cables to the loom.

As I said the battery cables put into 10mm split tube, I put the P3 connector end of the loom over the the steering column just under the speedo (I removed this it made the whole job easier).

The battery split tube I routed down behind the vinyl bulkhead mat directly in front of the handbrake, just to the right of the factory wiring, exit near the top of the gearbox tunnel and then poke it across the tunnel, under the plastic flap to the passenger side. I pulled the tunnel vinyl back to gain access.

Then on the passenger side I followed the bulkhead/gearbox tunnel intersection down to the floor and then followed the intersection of the gearbox tunnel and floor to the front of the seatbox.

As far as I could get into the corner I used a step drill to make a 24mm hole and then fitted that with a rubber grommet. I found this extremely hard trying to force the grommet in as there is 2 and 3 layers of aluminium here.

Once through here I then made another 24mm hole fitted with grommet in the top of the battery box wall which runs front to back to get the cables into the battery box. Connect all up as required.

The red and blue cables to run to the rear of the car I ran down the initial location behind the bullhead vinyl next to the other cables and followed the floor/gearbox tunnel intersection to the front of the seatbox under the handbrake. I made a hole in the corner the same as the other side with another grommet.

From the underside of the seatbox I used 13mm black irrigation poly pipe and jammed this into the grommet and ran this to the back of the car. I then fed the 6mm dual core into the poly pipe and fed it to the back where I made my connections into a Narva large 7pin socket (as they take 6mm wire and are rated to 30 amps) This socket I mounted into the round space in the rear crossmember. I picked up my brake light signal at the socket.

I cable tied the poly pipe along the top of the drivers side chassis rail. When I got to the rear just in front of the fuel filler pipe I changed back to the 10 split tube for its flexibility.

The grommets I used were a tight fit with the split tube and the poly pipe so should be waterproof.

Where the battery side split tube went under the car between the seatbox wall and the battery box wall, I covered this with heat shrink so that it would be waterproof.

The mounting bracket for the controller itself I tried the removable one but found it hung too low and I just didn't like the look of it. I used the other bracket and used the closest holes to the mounting surface so it would be nice and high and cut the rest of the sides off.

Obviously using this bracket you can't fix it in position and then mount the controller from the sides as the screws are against the side of the dash and the steering columns shroud.

To alleviate this I slotted the bracket so that you can slide the bracket (already fixed to the P3 unit) over the partially fitted fixing screws and then tighten with a small spanner. I also used a piece of 12mm wide 3mm thick aluminium bar behind the plastic and tapped it for 5mm set screws (hex head) for extra strength. If I need to remove it its just a matter of a couple of turns with a open end spanner, slide the unit with bracket attached out and unplug, to replace just reverse. Easy as and a hell of a lot stronger than the other bracket. The bottom of the unit is basically flush with the bottom of the steering column shroud so it well out of the way of your knees and it's still easy to reach.

Oh yeah, to fit it there you need to cut the column shroud approx half way across the old choke cable hole forward.

Well that's about it

I just thought, when you do get it powered up and going, every time you start the car (with no trailer attached) you will get a red alternating screen saying NO TRAILER CONNECTION, this goes for 2 minutes then it goes to the Tekonsha home screen as in my photo. When you switch the car off the P3 will stay lit for 15 minutes, this IS normal.

Mick

I thought about using the grommet in front of the steering column but seeing as though it sits just under the channel from the bonnet, I didn't want to wake the water ingress gods so I went the way I described.

I can adjust the contrast and brightness on the P3 screen if thats an issue at night.

You are right, you don't even notice the 'customised' column shroud.

Mick