Offroad-Express

I am blowing tail light fuses. looks like a dead short
It also controls all the dash lights and the front park lights
I have taken all the bulbs out of the outside lights and taken the complete dash apart to take all of the instrument and switch lights out of the circuit and still the short remains

Has anybody had this problem ???

Where do I look next ???

Have you checked your number plate light??

hiluxDave wrote:Have you checked your number plate light??

No ...
Missed that one ... back in 5 ...

Unplugged the plate lamps ... still a short ...

only thing left to do is trace all the wiring loom(s) from the fuse to each light socket and you will source your short.

My pic would have to be somewhere in the front as it takes most of the knocks and punishment, the rear is usualy protected well from within the skins of the body.

Just my 50c worth.

If you can, insert a test light into the fuse holder, this will allow you to have the circuit active whilst tracing the short.

Follow the loom from the rear of the vehicle back and at each connector point unplug the loom. If the short goes out you have found the section of loom that is damaged.

Good luck.

Matt.

Mattman wrote:If you can, insert a test light into the fuse holder, this will allow you to have the circuit active whilst tracing the short.

Follow the loom from the rear of the vehicle back and at each connector point unplug the loom. If the short goes out you have found the section of loom that is damaged.

Good luck.

Matt.

Made up a test light tonight and ground the plastic off the side of a blown fuse and soldered the wires to it ... so now I can plug it into the fuse holder ...


End to end on the loom is where I am at now ...

I posted here in case there was a spot that they always failed
The front of the wagon is full of Thompson's track mud all the connectors etc are full of it, but it has been fine for 4 weeks since then ...

OH well I guess I know what I am doing tomorrow night ...

I had a similar problem years ago but all my lights went haywire, indicators on when braking etc. I had crushed the wiring to my trailer plug and shorted wires.

dazza85 wrote:The front of the wagon is full of Thompson's track mud all the connectors etc are full of it, but it has been fine for 4 weeks since then ...

could be moisture in the loom causing the problem if its full of mud?

Sadam_Husain wrote:could be moisture in the loom causing the problem if its full of mud?

I have been wondering if that may be the case as we have had heaps of rain in the last 10 days, though it only started when the rain stopped.

I started with the back one and it came apart ok, but the one in front of t he petrol tank is being a pain

I have had a poke around the head lights and there is lots of dried mud in everything.

I'm thinking that under the fuse block could be worth checking

I probably won't get another crack at it 'till the weekend.

have you got a head unit? I have had similar issues in several different cars and trucks and traced it to poor, wrong or damaged wiring to the head unit, seems its also on the same fuse as rear lights and dash, you will probably find when the fuse blows your break lights still work? but they wont go if you have your lights on.

dazza85 wrote:I am blowing tail light fuses. looks like a dead short
It also controls all the dash lights and the front park lights
I have taken all the bulbs out of the outside lights and taken the complete dash apart to take all of the instrument and switch lights out of the circuit and still the short remains

Has anybody had this problem ???

Where do I look next ???

same thing just happened to my nissan mistral, put in two new fuses but would blow then in no time,

took it down to auto sparky, he unhooked my alarm from the lights ( so the lights dont flash when you turn the alarm on/off) it has seemed to fixed the problem

rangimotors wrote:have you got a head unit? I have had similar issues in several different cars and trucks and traced it to poor, wrong or damaged wiring to the head unit, seems its also on the same fuse as rear lights and dash, you will probably find when the fuse blows your break lights still work? but they wont go if you have your lights on.

Yes ..a brand new Sony ... the cheep one ... I think I checked with it unplugged ... will check again ...

MAHINDRACJ4A ... re Alarm don't have one yet, thats next payday

yea only my 2c but the head unit is where i would start, i have seen it time and time again (even did it myself a time or two before i realised) some factory head units light up when you turn your lights on so they have a power feed for this which if measured with a meter will have no voltage on it (unless your lights are on) and many make the mistake of assuming its an earth, or leaving it tapped to other wires or just leaving it flying around then when you turn your lights on, pop goes a fuse and it seems the obvious place to check are your lights since its what you turned on, there are other errors that can do it like a stuffed head unit, wrong wirring, a short in the wirring or even wet loom, have a go and see how you go, (could be way off the mark, but hey better to have to much info than not enough i no what its like to chase your tail around a vechicle for hours and get no where)

and when you say its brand new, who put it in?

rangimotors wrote:and when you say its brand new, who put it in?

New as in just brought it from the shop, installed by me ... understand what you are saying about the light feed ... going to unplug the head unit after tea ...

Well that was interesting
I did have a wire wrong ...
It seams that you were right there is a light feed to the radio plug.
Now it is not connected to anything

The worst of it is that this has not fixed the problem

really you have fixed the wirring, or chopped it out and not connected it back up yet? i would of thought that fixing that problem and replacing the fuse would sort your problems. maybe something else it wrong, ill have a think..

Fixed the radio wiring and left the extra wire unconnected as it should be.

Look forward to any other ideas you may have.

The truck is out side ... I don't have a shed that it will fit in so I''m on here instead of working on it.

all i can think of is its a short between either your full time power or your acc power, only other question is did the old head unit have a band expanded?

The band expander was connected to the acc power ...

I have been trying to get some of the loom connectors apart but some of them are really stubborn.
The short seems to be somewhere after the light switch is it is not there when the switch is off.

hmmm as ive never owned an isuzu maybe i've come to the end of my tiny knowledge, if i was you (hard to pin point without seeing it) i would be looking for various things that are powered when you turn lights no, i no im scratching for straws but some have clocks that light up when you turn lights on, and heater controls etc have you used any of there power feeds, earths or even just knocked a wire off well wiring up your headunit etc. I could be way off track but as i say without seeing it its very hard to trace the fault.. sorry i couldn't be more help.

dazza85 wrote:

rangimotors wrote:and when you say its brand new, who put it in?

New as in just brought it from the shop, installed by me ... understand what you are saying about the light feed ... going to unplug the head unit after tea ...

Hey.

i had this problem too when i put my pioneer headunit from my old car into my bighorn. blew heaps of fuses b4 i asked an autosparky.
the factory earth for the stereo wiring is connected to the earth for your dash and tail light fuse - dont use the factory earth wire just wire the headunit earth staight to the chassie/body. i just put my headunit earth to one of the bolts that secures the headunit in the metal mounting braket. works a treat for me, hope this helps.
Simon

dont use the factory earth wire just wire the headunit earth staight to the chassie/body

i second that

I have spent / wasted 3 days chasing a red herring

You guys were spot on

When I disconected the head unit I did not think about the fact that I had put the bulbs back into the front and back lights and so of course the test bulb plugged into the fuse holder is going to show a short ...

Went through it again and a friend came around to help and when we had spent another hour on it he asked if I had a amp meter
Poked that in, in place of the test bulb and its only 2 amps.

Thanks so much guys

More of those those good buggers

ok funny how another set of eyes sometimes helps alot, all good you have it sorted.