Help - Short Circuit

[Bushie]

98 Defender 300Tdi

I have a short on the circuit controlled by fuse 3 (Indicators, temp/fuel gauge, rear wiper washer) as best I can determine all the above circuits are OK which indicates the short is between the fuse and the header behind the speedo/instruments.

Anybody got any ideas on how to confirm this and if that is the problem how to rectify.
I'm beginning to suspect wiring has rubbed through but short of removing all the dash there's no way of seeing the wiring.


Martyn

[Chenz]

Sounds like you are stumped by this bloody short Martyn. I hope someone out there can give you some advice.

Or else it looks like out with the dash and trace it back - yuk

[Xtreme]

If you can locate each end of the suspect wire then disconnect it and run a temporary wire to see if it solves the problem. If it does then reroute the temporary wire and make it your permanent one.

[bee utey]

My trick to chase difficult shorts is to wire a high power halogen bulb instead of a fuse. When the short occurs the filament lights up and limits the current. 100W is 8 amps max, will still operate circuits while there's no short. This way you can isolate the short without wasting heaps of fuses.

[lardy]

Good luck on this one old bean, I still have the issue with the horn fuse blowing tried you enlightened suggestion gonna try the horn earth ...
Your earth all good on the applications ?

[Bushie]

My reasoning behind suspecting chaffing of wiring is sooner or later everything will go back OK, I suspect due to moving wiring around. Once you put everything back, connect everything up and go for a drive all will be fine for a while, hit a bump and you can hear the fuse go with a nice crack, so its obviously a dead short to earth.

Anyway got to work today so it's gonna be a job for the weekend.
I think I'll try Rogers suggestion, pretty sure I know where the ends are getting at them not so easy though.



Martyn

[Scouse]

There's a blue connector behind the instrument cluster that feeds 4 different circuits. If you can remove a pin/terminal at a time, you should be able to track down which circuit is the problem.

Let me know your email address & I'll send through screen shots of the wiring diagrams & connector.

[rar110]

I once had the front windscreen wire shorting behind the guage panel on the vertical steering column support that attaches to the firewall. I now have the support wrapped in electrical tape to help prevent damage to other wiring.

[Bushie]

{fingers crossed}
Looks like I have had some success, by using the info Scouse emailed, and my auto elec mate we isolated it to the park circuit for the rear wipers (pin 1 on header C285). Due to having heaps of other things to do I've just pulled the circuit and will do without the ability of the wiper to park for now :D.

When we get back I will try and narrow it down further, hopefully it's not inside the chassis.


Martyn

[JDNSW]

Sounds like the problem I had some years ago. It is inside the chassis!

Rear wiper does fine without the self parking!

John