Reversing sensors-how are they de-activated

[Sandgroper]

Thanks nanoo, I'll look it up tomorrow and print it out to show them.
Sandgroper.

[nanoo]

You'll find a little speel on the web site under Pajero - Examine - Accessories - Tow Pakage. I have the tow pack but have not used it as yet. Maybe it'll get a workout this weekend...I'll let you know if all is fine.

[adamd]

Hi,

I just wanted to make some comments as I have just had this problem and finally got it sorted.

I had a HR towbar put on my car but we used a genuine Mitsubishi wiring harness for the rear plug into the back of the car (relay was heaps quieter). Because we used the genuine wiring harness, I had expected that the reversing sensors would be automatically disconnected once a trailer was connected but I was sadly mistaken as the first time I went into reverse with a trailer on, the sensors went ballistic. I could successfully turn them off using the button to the left of the steering column, but I had to do this every time I selected reverse.

I took it back to the place that did the install and they had a look but said that it was installed and connected correctly. They managed to get the installation instructions for the MM tow bar kit and this started to shed some light on the issue.

The way the reversing sensors are deactivated is by a reed switch in the rear plug. If you have the correct plug, you will notice that when you open the flap there is a little magnet in the middle of the inside of the flap. This essentially creates an open circuit once the flap is opened. The wires that Walker talked about earlier in this thread are the wires that connect to this reed switch. It is also why you have to have this particular plug as standard plugs don?t have this switch.

The MM trailer wiring harness (part number MR935181) will not, by itself, allow you to make the connection allowing the reversing sensors to be automatically deactivated when the flap on the plug is opened. You have to have what is called the Reverse Parking Sensor (RPS) Patch Harness and this only comes with the complete MM tow bar kit (Part number MR935178). This kit includes the actual tow bar, all the connectors, wiring, shackles etc etc. Despite lots of calls, I was not able to buy this extra harness by itself.

I have attached a copy of the page that shows this extra harness (in Figure 16). In this same figure, the arrow labeled 1 is the lead that comes from the trailer wiring harness and was not connected to anything in my car. Once connected to the RPS system, this lead provides an earth and when the flap opens (and the earth circuit is therefore open) no earth is available hence the sensors do not work.

Now, if you don?t have the full genuine MM tow bar kit installed, all that you have to do to get this to work (yes I am getting to it!), is connect the free earth lead from the trailer wiring harness to the earth on the RPS box. I actually had someone do this for me but now that I know where to make the connection I figured I?ll let everyone else know as it is actually an easy connection to make. If you have a complete, genuine, MM tow bar kit installed and your reversing sensors do not automatically deactivate when a trailer is connected, yours hasn?t been installed correctly.

I?ll put another post up shortly showing the pictures of how to correctly connect the earth.

My reversing sensors now turn off when I open the flap on the trailer plug.

Page from installation guide showing the harness I don't have:

[adamd]

here is the plug at the back with magnet

1. Cut off the plug on the earth wire and solder new wire to it. The one here is the grey wire coming from the right (original plug has already been cut of and new wire (black) is soldered and taped in front of foam.



2. Run this wire down the right hand side of your car and over the driver's foot well...


...and over the tunnel to the passenger side footwell

[adamd]

3. Remove the plastic trim at the top of the passenger side foot well


4. Run the new wire around to the left side of the footwell with enough length to get the the RPS unit





5. Remove the RPS unit (1 screw) and solder the end of the new wire to the existing earth lead (black lead at bottom right of plug when viewed like this)


Now, when the trailer plug flap is opened, the reed switch causes the earth circuit to be open and your sensors will be deactivated.

Cheers,

Adam.

[Pete & Mon's NS]

Nice work Adam

Excellent write up and a cheap fix for those whose RPS isn't working properly or was not installed properly

Regards

Peter

[RalphEdward]

Adams Effort

Well done Adam,

I was chasing up this same problem for a mate when I came across this thread. You've saved me a few hours of my Saturday as I was going to do the same as you have, take a few photos to send him with the instructions.

I owe you a couple of these

Once again, well done!

Mark

[adamd]

No problems. Glad it helped.

If anyone wants the full installation guide just let me know. It's about 30mb all up. It's useful as it also goes through how to dismantle the rear trim panels.

Adam.

[nanoo]

No problems. Glad it helped.

If anyone wants the full installation guide just let me know. It's about 30mb all up. It's useful as it also goes through how to dismantle the rear trim panels.

Adam.

You've done a great job there Adam!

I approached my service guy about my sensors not turning off and he said that I have to push the button. I do have the mits. tow bar and correct wiring harness so it's looks like they haven't wired it correctly.

Well now I have some ammo to get the job done right. I would appreciate if you could send me the install guide!

Cheers
Andrew

[adamd]

Sorry, I've been away. I've managed to slim the file down (it's now only about 10Mb) and found somewhere to host it. Hopefully this links works OK

http://www.4shared.com/file/55877065/aeb6967b/Mit_towbar_fit_guide.html

For those that didn't buy the whole MM towbar kit but have the genuine MM wiring harnes, your car will probably look like 'View A' and 'View B' on page 7 as this is what I found when I took the car apart (remember I have the MM wiring harnes).

For those that have the whole MM towbar kit, you should have gotten the extra harness in 'Figure 15' on page 8. This is what allows you to connect the earth lead from the wiring harness.

Don't forget to have a look in the 'User Information' section on page 14 where it states that this is compatible with reversing sensors and that the RPS should shut off when the plug flap is opened. I love the way you can buy the plugs from them but not the rest of the wiring kit that makes it work!

Cheers,

Adam.

[Kemsley]

Further to this excellent post I have been unsuccessfully trying to get the dealer who fitted the towbar prior to new car delivery to fix the wiring to disconnect the parking sensors. They just keep on going round in circles and have finally suggested that I am stupid and that is what the button under the steering wheel is for.

Basically they say it is not possible with the factory fitted reverse parking sensors and is only possible with the park sensors fitted as an accessory. They have even stated that this is how it is worded on MMA?s web site. Talked to MMA but they cant help as they state that they are not technical!!! (the 1300 number). In any case MMA stated that if the tow bar was fitted by the dealer that they cannot assist anyway and I must take it up with the dealer.

So just to be clear could those who have the correctly fitted installation that disconnects the reverse sensors, please, could you confirm if you have the factory fitted reverse parking sensors.

Thanks.

[Pete & Mon's NS]

... In any case MMA stated that if the tow bar was fitted by the dealer that they cannot assist anyway and I must take it up with the dealer....

Don't you just hate the run around? You'd think they would be doing better for a customer thats just dropped more than $60k on their top of the line vehicle....

[stevenbowden]

I too would like to know the answer to this as I think I am just about to go into battle as well. We had the towbar fitted pre delivery and the plug doesn't disconnect the parking sensors. I haven't let the dealer know yet that I want it fixed at the 1500km service and I am trying to get as many facts together first before I put it too them.

Regards
Steve

[apsilon]

I'll be ordering my NS in the next couple of weeks and will be getting the towbar and am considering the parking sensors. I've never had parking sensors before but think they may be useful on a tall vehicle with limited visibility close to the ground at the rear. Is there a way to test that they're disabled correctly without a trailer to plug into? Either a couple of pins to jumper or a plug I could wire up and connect?

Reason being that I usually have them write into the contract that the pre delivery fee is refundable if anything is missed/not checked/not working at delivery. I check and test everything before taking delivery of a vehicle. Wouldn't be the first time I've saved myself $1k+ at the last minute.

[stevenbowden]

I would assume that if you look at the installed plug and if it is the same as the one shown here that includes the magnet, it should be installed correctly.

I think that you might be able to test it when the flap on the plug is open the circuit is broken and therefore the reversing sensors wouldn't work. I can't try this as I don't have the plug with the magnet so I can't say if this method would work or not.

Regards
Steve