Replacement Rear Fog blowing fuse

[eppiblue]

Hi. Ive had him for almost a year now and its MOT time! He had a rear fog light hanging from the bumper when I got him but I quick managed to snap it off in some dodgy camping field. Ive since purchased a new fog light but once Ive wired it up and I turn on the fog spots, it immediately cooks the 15A fuse.

Im not much of a sparky so any advice is appreciated.

This is the light I got -

All Ive done is taken the already available wiring (from the previous light - 1 earth and 1 live) and extended it with another few cm of 8amp auto wire, routed it into the back of the light and connected it to the two terminals on the light bracket thingy.

Why would it be blowing the fuse everytime I turn it on?

[haydn callow]

You must have a short somwhere or perhaps a faulty light unit.....Check everything again.....how did you connect the "extra" bit of wire ??

[eppiblue]

with a 15amp piece of connector strip.

the connection to the light terminals has been done by inserted the exposed wire thru some little holes (like cotton thru a needle hole) and then wrapped around tightly. I dont have a solder iron! And the wires arent touching each other.

[bigdaddycain]

On the surface is sounds as if you have connected -to+ve and vice versa...(reversed polarities) Try swapping the connections over and try the switch again.

[jaylee]

with a 15amp piece of connector strip.

the connection to the light terminals has been done by inserted the exposed wire thru some little holes (like cotton thru a needle hole) and then wrapped around tightly. I dont have a solder iron! And the wires arent touching each other.

A standard crimp connection female spade terminal would connect up to the - & + terminals in the fog lamp... I use the un-shielded variety then shrink-wrap like this example to avoid shorting... (Its a cramped space in there, easier to fit!)



I would hazard a guess there maybe a short at the join to your extension, possibly inadequate insulation between the two wires connections??

All Ive done is taken the already available wiring (from the previous light - 1 earth and 1 live) and extended it with another few cm of 8amp auto wire, routed it into the back of the light and connected it to the two terminals on the light bracket thingy.

Why would it be blowing the fuse everytime I turn it on?

Not alot can really go wrong with the lamp unit itself...

[scanner]

On the surface is sounds as if you have connected -to+ve and vice versa...(reversed polarities) Try swapping the connections over and try the switch again.

Fog lights don't have a polarity

[bigdaddycain]

On the surface is sounds as if you have connected -to+ve and vice versa...(reversed polarities) Try swapping the connections over and try the switch again.

Fog lights don't have a polarity

You lost me there Scanner... Two wires, one neg, one pos... If neg wire went to pos contact (and vice versa)there is a reversed polarity which would blow the fuse

"Electrical polarity (positive and negative) is present in every electrical circuit. Electrons flow from the negative pole to the positive pole. In a direct current (DC) circuit, one pole is always negative, the other pole is always positive and the electrons flow in one direction only. In an alternating current (AC) circuit the two poles alternate between negative and positive and the direction of the electron flow continually reverses."

[haydn callow]

It doesn't matter which wire you connect to which bulb terminal...But if you create a "short" by contacting Pos to Neg at any point (or pos to earth) then it does......bulbs are not polarity sensitive in themselves....unless they are LED's

[scanner]

Nope - the element in a tungsten bulb doesn't care which way current flows and that's all a fog light is - a bulb in a box.

The bulb in this case is a single pole one and it doesn't matter if the pole or the case is +tive or -tive.

[bigdaddycain]

And i thought i'd always dropped lucky with "guessing" the connections were the correct way round!

[bigdaddycain]

So as Jaylee points out above, the chances are a short at the cable extension.

[haydn callow]

I would think so !!! also I would not trust the twisted connections....they will "crud" up and fail...could even cause a short.....Get some small crimp terminals from Halfords/Maplins as suggested above

[bigdaddycain]

I remember some fella trying to tell me that a wire shouldn't be twisted into a spade connector as it takes the electricity too long to reach the bulb! When in fact the real reason is that it shouldn't be twisted into the connector because the electricity will get dizzy and subsequent light output will swirl around.

[haydn callow]

That depends which way (clock/anticlockwise) you twist it and wether you are north/south of the equator......

[jaylee]

If a tree falls in a forest & no one is around to hear it, does it make a sound....???

My theory is the falling tree yells timber on the way down.... You got to see it not to believe it, according to the experts...

http://www.youtube.com/watch?v=DfPeprQ7oGc