towbar woes

[cupra tdi]

fitted a towbar and wiring kit to the car(not seat)everything works fine but after repeated use of the brakes the fuse blows.anyone know how to fix this other than spending £51 +vat at the dealers

 

[m0rk]

bigger fuse? now you're running more lights, the current may well be greater

 

[hocrss]

check wiring inside rear of plug maybe loose/touching & earthing out.
Unlikely to be a problem with car wiring

 

[TheOtherSimon]

Have you had a look at the trailer wiring. Is the resistance of the brake circuit the same as the foglight circuit?

You shouldn't need to uprate the fuse.

Simon.

 

[cupra tdi]

a bigger fuse doesn't help,and the trailer wiring is alright as i can put it behind other cars with no prob's.the wiring in rear light cluster and plug seems ok.when the fuse blows if it is replaced it will blow straight away unless the trailer plug is removed first(even though the brakes are not pressed) so a capacitor or something must be built into the system which charges up as the brakes are used and this then causes the fuse to blow.i think i am just going to have to by the seat part but it galls me to do it since the dealer can't even say what is in the wiring kit

 

[TheOtherSimon]

A capacitor is really really the wrong answer.

You need to find out why the system is drawing so much current that it is blowing the fuse. Either your car has faulty wiring, and the trailer is pushing it over the edge, or the trailer wiring is faulty.

What is the resistance of the trailer brake circuit?
What is the resistance of the car brake circuit?

Both circuits should be about 3-4 ohms, assuming that you have a pair of 21W bulbs in the circuit.
With all four bulbs the system should be drawing 6 or 7 Amps, and no more.

Simon.

 

[amos3]

Does this only happen when the trailer is attached?

Are the wires soldered or are u using those blue connector things?

I fitted all of my tow bar my self but i got the wiring done by my local Car stereo shop, it may be worth getting a local specialist to look over it before getting seat to bleed you dry. All he did was strip the necesary wires back and solder onto them and ive had no probs. But mine is only powering a regular lighting board.

 

[cupra tdi]

hi, it does only happen when the trailer is connected,and i have soldered the wiring rather than scotchblocs.

 

[Sooty torques]

The advice to go to a decent independent leccy is good advice... There are lots of good, honest towbar fitters who'll check the wiring for you at very little cost. I had a similar prob with a faulty earth somewhere in the electrics of a Citroen I used to tow with - yeah, I know, Cit's and electrics in the same sentence = trouble... A guy working from a tiny little shop sorted it out extremely efficiently and very neatly. Had all my towbars fitted by the same guy since, lovely neat work - he prides himself in his job. Have you tried asking around for any recommendations? Caravan / camping shops are good starting points for advice.

 

[cupra tdi]

i had to buy the dealer kit.it comes with a new hazard light switch
connected it up and no more blown fuses.the 7 pin socket also had a couple of wires running into a plug on its side,i.e not the trailer socket