View Full Version : disable reverse sensors with trailer - 12pin flat socket with reed switch
PeterOZ
24th September 2025, 03:32 PM
Gday All,
I'm prepping the D3 in order to tow the new caravan I will be getting soon, not a huge mansion on wheels just a modest 14ft on road with some nice creature comforts to suit a bachelor. [bigwhistle]
I'm currently looking at getting the 12 pin flat socket which my van is fitted with and I have to have on the D3.
I did see one in on Repco website that they have 12 pin flat with reed switch in order to disable the reverse sensors.
There are 2 types, normally open or a normally closed type now I would think the D3 requires normally closed but would be nice to know for sure.
Does anybody know?
12 Pin Flat Trailer Socket with Reed Switch for use with Normally Closed Circuits
Part No. 82073BL
narva-trailer-socket... (https://www.repco.com.au/4wd-adventure-escape/towing-equipment/trailer-plugs-adaptors/narva-trailer-socket-12-pin-flat-with-reed-switch-normally-closed-circuit-82073bl/p/A9313321?srsltid=AfmBOorhJQSp8PIadCk3Ph8N-tVyB-VVtmp6ws3zrtG6GxlFcVwyIs9j)
hope somebody knows.
cheers
Peter
woko
24th September 2025, 04:04 PM
The Discovery 3 does not use a reed switch. Just use a standard 12 pin plug.
You will have to remove the blue wire in the plug as it is used for fog lights. The 12 pin doesn't have fog lights.
The discovery uses the extra load out on the circuit to disable the reverse sensors. If your caravan has led lights, you will need a resistor adapter to have an extra load on the circuit. If you don't, the led blinkers will flash constantly
I don't like adapters. I have a system mounted in the car with relays and load resistors that I turn on and off if I have a trailer on.
SeanC
26th September 2025, 12:19 PM
I also have a module in the compartment behind the passenger’s side rear light cluster. It has a switch to turn off the rear sensors when towing.
PeterOZ
26th September 2025, 12:29 PM
I have that same module, think it was by lineardesign.com here in oz and just read the blurb on their website which advised it disables the reversing sensors.
I am going to wire it into the D3 rear compartment so should not need the reed switch plug.
gavinwibrow
26th September 2025, 01:32 PM
Gday All,
I'm prepping the D3 in order to tow the new caravan I will be getting soon, not a huge mansion on wheels just a modest 14ft on road with some nice creature comforts to suit a bachelor. [bigwhistle]
I'm currently looking at getting the 12 pin flat socket which my van is fitted with and I have to have on the D3.
I did see one in on Repco website that they have 12 pin flat with reed switch in order to disable the reverse sensors.
There are 2 types, normally open or a normally closed type now I would think the D3 requires normally closed but would be nice to know for sure.
Does anybody know?
12 Pin Flat Trailer Socket with Reed Switch for use with Normally Closed Circuits
Part No. 82073BL
narva-trailer-socket... (https://www.repco.com.au/4wd-adventure-escape/towing-equipment/trailer-plugs-adaptors/narva-trailer-socket-12-pin-flat-with-reed-switch-normally-closed-circuit-82073bl/p/A9313321?srsltid=AfmBOorhJQSp8PIadCk3Ph8N-tVyB-VVtmp6ws3zrtG6GxlFcVwyIs9j)
hope somebody knows.
cheers
Peter
Can not the D3 use the semiclear plastic covers that work well on the inner sensors on my D4?
There are a number of posts on here - most people seem to have purchased the covers from Bunnings.
Redback
26th September 2025, 02:30 PM
We turned our reverse sensors off with our diagnostic tool.
BradC
27th September 2025, 10:49 AM
Can not the D3 use the semiclear plastic covers that work well on the inner sensors on my D4?
Why would you half arse it with those? If you set the car up properly with load resistors (and pulse buster relays for the D3) then the vehicle knows it has a trailer on, disables the reversing sensors and changes the transmission and engine mapping to be appropriate for towing.
Now, if you were really clever you'd build those into the car and wire them up to the reed switch in the 12 pin socket.
loanrangie
27th September 2025, 11:19 AM
The clear adhesives dots work if you have a mitch hitch or other high mount hitch, if the fit resistors and relays you wont need to turn the sensors off as once the trailer is detected they will be turned off by the canbus.
discomatt69
27th September 2025, 02:49 PM
I have tried but can’t work out a fix but my D 4 senses a trailer , dash indicates a trailer, LED lights work correct on trailers yet the reverse sensor stat active and wo eh k every time I put it in reverse, drives me nuts when trying to reverse the van into tight spots and the beepers are going off
Tombie
29th September 2025, 11:02 AM
I have tried but can’t work out a fix but my D 4 senses a trailer , dash indicates a trailer, LED lights work correct on trailers yet the reverse sensor stat active and wo eh k every time I put it in reverse, drives me nuts when trying to reverse the van into tight spots and the beepers are going off
SHort term:- You have a HSE. Just press the dash button and disable them.
Long term, you have a glitch [biggrin] check your firmware for the control modules are up to date, and that something hasnt been changed by mistake in the CCF
discomatt69
29th September 2025, 03:38 PM
SHort term:- You have a HSE. Just press the dash button and disable them.
Long term, you have a glitch [biggrin] check your firmware for the control modules are up to date, and that something hasnt been changed by mistake in the CCF
Button on the dash doesn’t turn them off either, works on the front but not the rear, they have had me baffled for years, haven’t checked firmware and CCF
DiscoJeffster
29th September 2025, 07:00 PM
Button on the dash doesn’t turn them off either, works on the front but not the rear, they have had me baffled for years, haven’t checked firmware and CCF
Yeah that’s not right. I have a HSE and the button disables both for me
veebs
1st October 2025, 03:43 PM
The Gap Diagnostics tool shows the configuration changed in 2012 - possibly the 2013 button behaves differently to the 2010/2011 years
I've retrofitted the button on to my 2010 SE - i wonder if I can fiddle with the CCF to disable the reverse sensors when backing up. Hmm...
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