Before removing your old cable, you need to source a new one together with a new plug. You could buy three metres of cable and a plug and assemble it yourself but at approximately £34 delivered (eBay) you might think it makes more sense to buy one ready made-up. I did.

These are the tools you will need to do the job.


L-R: crimp-on female spade terminals (you will need 8 x red and 5 x blue – they don’t have to be fully insulated); ratchet crimping tool (a non-ratchet type will not develop sufficient pressure to make a good, reliable joint); flat screwdriver; Stanley knife for stripping back cable sheathing; wire stripper; wire cutters; new cable and plug; large nylon cable ties (not shown).

Before working underneath your caravan, you need to make sure that you will be safe. You will have ample room to work if you raise the front of the van on the jockey wheel and lower the corner steadies for stability. Support the chassis on axle stands or piles of bricks and to be doubly secure, put the handbrake on or chock the wheels to prevent movement.



To remove the old cable you need to trace it back to the white junction box under the caravan floor.



The bottom of the junction box is retained at each corner by a 90° quick-release screw. As you can see, the heads of the plastic screws accept a broad blade screwdriver and need turning so that each '1' faces its corresponding '0'. The cover can then be waggled free.



This is what you will see when you remove the cover.


The terminal blocks are loose within the junction box and are simply crammed inside.

You could draw a diagram of which wire from the 13-core cable goes where but a better way is to leave the wires attached and simply snip them off where they enter the junction box leaving approximately two inch tails. (As you can see, a photograph doesn’t really help.) This way you can replace them correctly, one at a time.



Note: Check that the female spade terminals are firmly attached to their respective male blades before cutting the tails as they may be loose and fall off as you snip them. Also check for any loose terminals. Quality control at the factory wasn’t always as good as it might have been and poorly crimped terminals are not uncommon.

The next job is to prepare the ends of the new cable by stripping back the outer sheathing, baring the ends of the wires and crimping on the correct sized terminals. This is best done at the bench/kitchen table as you need to make strong, clean joints. Give them a good tug to ensure that the fitting has really gripped the copper conductor. The eight x 1.5mm dia. wires will need red terminals and the 5 x 2.5mm dia. wires require blue ones. Cut the outer sheathing of your cable back far enough to allow you to connect all the terminals without straining them. You can afford to be generous with the length as you will have ample cable and the wires will easily fit inside the large junction box.



Note: the white/blue wire from pin 12 of the plug is not used but you may find that the original has been fitted with a terminal and parked on an unused piece of terminal strip. If so then do the same with your new wire.

You will find that a 3 metre cable is a bit too long for an Eriba but don't cut it short. Secure it to the chassis instead with cable ties so as to leave a bit spare in case you drag the new one along the road sometime in the future.

Back underneath the caravan, thread the new cable back through the various supports and once around the main chassis member before replacing the spade connectors on their terminals one at a time. Replace the junction box lid and turn the fastenings through 90° to lock them in place.
You may find it necessary to move one of the plastic P-clips that hold the cable to the underside of the floor to free up an extra few inches of cable for connecting to the car and when you are satisfied that you have enough cable available at the plug end to connect to your car without straining it, secure the cable to the chassis with the cable ties.


This slightly out of focus shot shows how the cable is looped around the chassis member.

Finally, all that remains is to connect caravan to car and do a full systems check. As well as the lights and indicators, be sure to check that the fridge 12v red light and the green light on the Schaudt booster (if fitted) both come on when the car engine is running.

To prevent future problems with the cable touching the road surface, secure it to the drawbar with a bungy.

(With thanks to JohnE for his support and practical advice while undertaking this project)