Tow bar earth problem

[pierreandre]

Good morning guys
I think I have an earth problem on the tow bar connection of the pajero. I've tested with more than one trailer, and the symptoms are as follows:
1. All lights work correctly when switched on individually.
2. The lights go crazy when the left or right indicators are on together with the brake lights or tail lights. For example, if you have the brake lights on and switch on the right indicator, the left brake light starts flickering.

I assume the tow bar connector is not properly grounded. Is it as simple as connecting pin 3 to the vehicle body?

[4ePikanini]

Don't use the hitch as ground. The ground is one of the 7 pins.

Do your troubleshooting with the plug connected and the towball unhitched.

[4ePajero]

What Marius said.
Attached the 7-pin connections for a trailer.

Don't trust the trailer lights when checking the car side of the plug. Use an AVO meter or test bulb.

Don't trust the car's plug when testing the trailer's wiring. Use a fused 12V source.

7 pin wiring - colour.gif (9.31 KiB) Viewed 2308 times

[pierreandre]

Thanks for the info. I've already gone through the steps to determine where the fault lies.

The problem seems to be with the earth connection on the car, i.e. pin number 3. It doesn't seem to be connected to earth, althougth there is a wire from the harness connected to it. Perhaps this wire was damaged somehow. My question is: Can I make sure that I have a proper earth connection by just connecting it to the towbar assembly, or do I need to run a new earth wire from somewhere else?

[tonton]

... My question is: Can I make sure that I have a proper earth connection by just connecting it to the towbar assembly, or do I need to run a new earth wire from somewhere else?

Pierreandre,

That should work, as the car's earth is connected to the chassis in any case. As long as it connects the trailer via the plug (pin # 3), and not via the towbar. Remember - the trailer's body is not earthed properly, so the neutral (earth) must be wired right up to each lightbulb of the trailer.

Anton

[paw_by_paw]

Pierre-andre,
I would suggest check where the harness from towbar origanated from and start checking where the earth was tapped in .
A earth fault can play havoc with your electrical system.
Whilst you are at it check all your earth connections , remove , clean and re-install. I had a stupid fault with my ABS not activating properly and after Mitsu suggested to change the ABS relays and pump I found an earth connection underneath the unit who has corroded a bit , cleaned it and no problems so far.

[paw_by_paw]

Pierreandre,
Forgot to mention something here. My towbar was tapped from where the rear harness exits the vehicle on left just infront of the wheel arch. What they did (the previous owner) was to use thse blue plastic connectors to join wires. I removed all of them , soldered the wires together , taped it , seperately installed these wire protectors plastic stripping over it and the taped the whole bunch closed with a good insulation tape. I only use 3m tape.
Regards

[SimonB]

What Marius said.
Attached the 7-pin connections for a trailer.

Don't trust the trailer lights when checking the car side of the plug. Use an AVO meter or test bulb.

Don't trust the car's plug when testing the trailer's wiring. Use a fused 12V source.

To clarify something here

This diagram is for the TRAILER SIDE... not the CAR SIDE. Which I found to my embarassment today

The CCW numbers should have given it away.