electrics...

[speedy blue]

a week ago rear offside light wasnt working had resistance in cable from backlight to light switch on dashboard .this week went out and nowwhen i turn main headlights on from side lights it blows 20amp fuse any ideas if are there are any relays although i cant hear them or other connections that might be loose and there wherabouts in the car ... many thanks

[bazz24]

im no expert but you could have a broken wire.  

like i sayed im no expert so im probably wrong  

have you checked all you wires?

[speedy blue]

i think i have a loose/boken wire but cannot find it at the mo, i would like to know how the lights are wired and where they go when they leave the back of the dashboard rocker switch. all help and ideas are greatfully accepted dudes cheers

[NRW]

It would only blow a fuse if there is a short somewhere. Check the loom and make sure it's not being chaffed somehwere and shorting to the chasis. The only idea I have at the mo

[bazz24]

i see your a fellow DUDE     .

   the wires should come out of the dash then through the top of the gbox tunnel/through the tunnel to the back of the car. they should be cliped or cable tied to the chassis.

[timandchris]

def sounds like a short.

which fuse is blowing? - on our car (SEIW madness recent) the only 20A fuse is for the fuel pump.

do you have a multimeter?

[speedy blue]

have got multimeter all ican say is that theres a 20a fuse that blows as soon as i put main beam on its fine with dipped beam and rear os light has never worked but mhen using meter there is resistance between back of dash switch and the bulb holder at rear of car two seperate probs but struggling with both.

[timandchris]

yes but trying to identify which fuse it is, to help track down the fault - if it's like mine there are two banks of six fuses each - bank A goes

10A

10A

15A

15A

15A

10A

Bank B goes

20A

10A

10A

10A

10A

15A

I believe older cars had a different arrangement - there is a wiring diagram on westfield world -

http://westfield-world.com/wiring_menu.html

but my chassis harness certainly differs from this incl e.g. number of fuses.

sorry may not be helping

[Hammy]

The high resistance you've measured for the back light stands a good chance of being a corroded connector -those under the rear arch are a favourite, i'd check those first.

To find what looks like a short for the headlamp I'd  discconect the lamp from the underbonnect connector - follow wires back to radiator area ( likely fault area is inside the headlamp shell) . Disconnect here and use your meter to check for the short to chassis  from each connector of the connector end that goes to the headlamp ( if that makes sense!). If there is no short here check the other side of the connector which goes back into the car harness ( battery disconnected for this) to see if there is a short- if there is follow the wiring back by hand and look for chafing to find your fault.

Also look at the back of the switch for a wiring fault here,

Faults are usually connectors -giving high resistance or earth connections to bulb holders ( giving the rear light type problem)  OR.. for the headlamp a fault at the switch end or the lamp end or a wire worn through and shorting to the chassis or another earth wire in between.

good luck