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smoke, burning, much crying as loom catches fire
saigonij - 29/7/07 at 07:10 PM

bummer!

i had the rapidfit loom wired in to the sierra stalks, except that i had used the Washer return as the earth path for the lights. this was because it went to earth when the lights came on....

anyway, while testing to see if anything on the wiper stalk went live, i must have pushed the wiper stalk back to the rear squirt position... the rear washer return that WAS earth, went live shorting out one of the earth wires...

it went hot, then hotter, then so hot it started to melt the wire insulation....

thankfully i was able to stop leaning on the wiper stalk and it just melted the insulation a bit in places.... the rest of the loom was fine ( after a very careful inspection ).

could have been much worse.....


nitram38 - 29/7/07 at 07:17 PM

A little tip for anyone.
Use an old style battery charger instead of a battery while you are checking your work.
That way you will blow a small fuse in the charger rather than have a couple of hundred amps from a battery.


BenB - 29/7/07 at 07:19 PM

Bad luck......

Shouldn't the loom (and the switches) be protected by fuses or have you got unfused supplies (naughty naughty!!!)...


indykid - 29/7/07 at 07:27 PM

or.......just put a fuse holder in a wire connected between your battery positive connector and the battery. you can increase the value of the fuse as you test circuits with more and more current draw then.

saves getting a battery charger if you don't have one.

tom


saigonij - 29/7/07 at 07:29 PM

no, i have fuses etc. this was where the positive charge was backed up down an earth wire, causing a short circuit.


BenB - 29/7/07 at 08:59 PM

Yeh- but shouldn't all the +ves be fused? IE there should be a fuse somewhere in the circuit!!


saigonij - 29/7/07 at 09:07 PM

im at a loss for an answer on that one.

all the fuses in the fuel box were fine, it was just this one earth wire that was melted.

once i replaced the wire everything was working as it was before ( i also corrected the fault ).

i don tknow where the feed was coming from, but presumably the earth wire gave out before the fuse did, or the feed came from an un fused wire - perhaps a "feature" of the standard rapidfit loom.

ill try and give some more answers if i can.


jollygreengiant - 30/7/07 at 01:34 AM

quote:
Originally posted by saigonij
im at a loss for an answer on that one.

all the fuses in the fuel box were fine, it was just this one earth wire that was melted.

once i replaced the wire everything was working as it was before ( i also corrected the fault ).

i don tknow where the feed was coming from, but presumably the earth wire gave out before the fuse did, or the feed came from an un fused wire - perhaps a "feature" of the standard rapidfit loom.

ill try and give some more answers if i can.


Ford use the same pump for the front AND rear screens. By switching the polarity of the circuit they use 1 pump and save money. Rotate pump one way and it pumps to the front screen, reverse polarity and the pump rotates the other way and water comes out of another outlet pipe and goes to the rear screen.
So the moral of the story is that you should not rely on washer pump earth to be an earth because it reverses polarity through the switch (if STILL fitted).


Hope this helps.

[Edited on 30/7/07 by jollygreengiant]


saigonij - 30/7/07 at 07:28 AM

sounds like the explaination...

what i think happened was that we were struggling with the stalks, and we found a wire that went to earth when the lights came on - so we thought this must have been the wire to use.

however, it seems to have been the washer return. that - as you say, reverses polarity when you pull the rear washer on...

to make it worse, on RapidFit looms, the side lights feed to the stalks is direct from the battery, so there is no fuse to blow...

this is why the wire fried and no fuse blew, cause there is no fuse on that circuit...


saigonij - 30/7/07 at 07:41 AM

i checked the wiring loom, and other than 1 earth wire that had melted leaving it stuck to another wire at certain points, nothing else seemed to have been damaged...

im a bit paranoid now though, so im wondering if i should replace the loom....

im 100% sure its ok, and where the wire had gotten stuck to another wire, i inspected it carefully....

just a bit paranoid...


rusty - 30/7/07 at 05:42 PM

Except from the main feed to the starter and maybe the altanator charge wire all curcuits should be fused.


indykid - 30/7/07 at 10:15 PM

even the stock loom in a sierra had circuits that were permanently live and unfused. i'm pretty sure the coil is run unfused too, just taken from the switched supply from the ignition barrel.

you could put a 50 amp fuse between the battery and the main positive feed, but it's not gonna stop a 5A wire burning out.

tom


tks - 24/5/08 at 02:05 PM

yupsz..

thats the reason all your wires should be more powerfull then your fuses..

else the wire just melts and the fuses won't pop.

You will need to build a star topology

the incomeing one is fused and the outgoing ones to!!

Tks