Trailer Brake Controller Gremlins (1 Viewer)

[hkeller]

I just install a Tenkonsha Prodigy PS on our 2004 LX. It is a plug and play into a factory wiring harness. Well, not when the LX is hook to the trailer and the ignition is off, the following things occur: (i) the AHC height level indicator stays light; (ii) the headlamps on indicator stays lit; (iii) the remote locks don't work and, (iv) the rear wiper runs erratically. Any thoughts? Sounds like a ground issue, but where? Weird!

 

[arcteryx]

You mean a P3? Did the brake controller come with the harness that goes under the dash and plugs in? If so, you need to ground the wire, did you do that?

I posted a month ago on how to install the wire, and there is another one in the FAQ. You may want to give that a read.

 

[hkeller]

Yeah. P3. Found appears connected. Problem in the trailer?

 

[hkeller]

Darn auto fill. Ground appears connected.

 

[arcteryx]

Ok, it could be your trailer. I had to put on a new 7-way connector. I spent a little more and got one that had a tester built into it from Autozone, so I could tell if everything was good from the vehicle. It saved me quite a bit of time. Also, this is where it's handy to have another vehicle or trailer to test with, do you have one or a friend who does?

 

[Sandroad]

Do things work ok with the ignition on?

Do you have the factory tow package with hitch, trailer light converter, and OEM 7 pin connector in your LX? If not, it could the truck side that’s a problem. Aftermarket converters can be good, but only if wired correctly. If it’s all OEM in the truck, then it’s most likely the trailer.

What’s the history of the trailer? Factory wiring or the usual spaghetti pile of questionable wiring/connectors from years of wiring problems?

My P3 was plug and play for my truck/trailer, but I did have to replace the trailer brake lights with incandescent because the LED bulbs it came with didn’t draw enough current to have the converter work properly. That caused issues on the trailer side, but not the truck side.

My guess; the trailer 7 pin connector is not wired properly.

 

[ToHiHy]

Have the same thing happen with my sled trailer. It back feeds from the battery for the brakes. Other trailers with brakes don't. In my research it appears to be a 2004 issue. I just unplug the trailer when I park.

 

[hkeller]

Lovely. What up with all 2004 electrical issues like MFD, Bluetooth, etc.?

 

[Joe Bob]

I just install a Tenkonsha Prodigy PS on our 2004 LX. It is a plug and play into a factory wiring harness. Well, not when the LX is hook to the trailer and the ignition is off, the following things occur: (i) the AHC height level indicator stays light; (ii) the headlamps on indicator stays lit; (iii) the remote locks don't work and, (iv) the rear wiper runs erratically. Any thoughts? Sounds like a ground issue, but where? Weird!

Do you have a pick of where the plug is? I can't find it anywhere under the steering column. I have an 06 lx.

 

[SICARIO]

Your problem is trailer battery back feeding into your vehicle after it’s turned off.

There is a factory relay assembly (you need a relay to interrupt the power) to solve the problem. Unfortunately they don’t wire up the relay assembly correctly, and it needs to be modified. It’s not very difficult to do, and there’s a thread that shows how to do it. I’ll look for it and post a link.

Link: 04 LX470 AHC, brake controller, & Electrical Issues Question

Here’s the relay assembly: PN-82241-60100