towbar electrics

[cazone]

Hi all, my son has been having trouble with his towbar electrics for a few days now, and we have asked for advice, and recieved, some excellent replies.

But the problem is still ongoing. In the beginning, he was having trouble with indicators, and roadlights, brakes, ect. I.e. there was nothing when he plugged into his towbar. He followed the advice given, he put on a new 7 pin plug to connect to the towbar, but still nothing.

Now he finds that when he disconnects the green and yellow earth that attaches to the caravan chassis, everything works ok, but when he reconnects it, nothing will work.Does anyone know if it is safe with out the green end yellow wire connected. There is a white wire connected to the rear caravan lights, which he thinks is an earth wire.

Thanks for any info

Cheers, Roy.

 

[antrimboy]

The earth to the road lights should be white, connected to pin 3 on the 7 pin plug. Not sure what the green and white wire is for, but in any case, the earth for the road lights shouldn't be connected to the chassis, so, if he connects the white wire up properly, and all the lights work properly, he should have no worries.

 

[ProfJohnL]

Hello Roy,

The information you have supplied in this post has set some alarm bells ringing.

The green/Yellow wire is almost certainly the mains earth bonding strap to the caravan chassis. This must not be disconnected as it forms part of the mains power installation's safety requirements. It should not affect 12V road lights.

If the disconnection of the Green/Yellow wire makes a difference then this points to the possibility that some thing else may be wrong, and I strongly urge you to have a competent electrician check out the mains systems for your safety.

As for the road lights, 12V lighting problems often turn out to be caused by corrosion on wring connectors, or broken wires. Its worth opening each light cluster and just make sure that all the connections are rust/corrosion free. A light application of Petroleum jelly on wiring connection's will help to keep them in good condition by preventing water and air getting at them.

Eddie is correct about the colour of the 12v negative return(Not Earth return)

All electrical items should be connected to their respective power sources using continuous wire for both positive and negative connections. The caravan chassis should not be relied on to act as a power conductor for any appliance or fitting, but for safety it should be earth bonded.

conductor

 

[antrimboy]

Many thanks for correcting my mistake John - 'twas a long day!

 

[xtrailman]

roy

Your son needs to take his car to a towbar fitter, get it connected to the test lighting rig. This will test the socket under LOAD, this is important as any poor connections such as poor earth connections will be flag up. Only then would i have confidence the problem is NOT the socket.

Assuming the car is ok, my next step would be to strip the caravan plug and check for poor connections or corrosion. If not fault is found her, then proceed to the end off the back flex cable

locate the place were it enters the caravan, you should find some connectors, using a multimeter at this point check for voltage between the road lights in sequence but ensure you put the black meter lead onto the white wire in the black flex, NOT any of the other two white wires in the grey cable.

You will obviously require the car to be connected to the caravan.

If no fault is found proceed to the light units themselves.

Do not remove any earth bonding wires from the chassis, they are their for your protection.

 

[phillip_374558452]

why dont you try the van on another car and car on another van this will tell you which is at fault as said befour never disconect the yellow/green cable as this is the mains earth

 

[cazone]

Hi all, thanks for all your replies, my son stripped the rear caravan lights, and found a corroded terminal. He replaced this, and all seems to be working now.

Cheers , Roy.

 

[ProfJohnL]

Hello Roy,

I'm glad he found the fault on the 12V systems, but I refer you to my post above concerning the effect of disconnecting the mains Earth Bond. That should not have affected the 12V lights at all

Your son must get the mains system checked as it could be unsafe.