What's blowing my fuse?

Phil Robson

Well-Known Member
BOP's indicators stopped working whilst I was driving yesterday, together with the temp, fuel & oil pressure gauges. I also later found out the brake lights weren't working ...:oops:

I found the relevant fuse & replaced it with the correct one (25 amp) only to find it instantly blew again :(

How can I trace the fault, please?
 
Hi, It's obviously a dead short, so replace the fuse with a bulb on a couple of fly leads which will light up. Then go round disconnecting and checking the various covered items and check the loom for signs of it having chaffed through until the light goes out and that will be your culprit.

Colin
 
I've removed the gauges that are affected by the fuse & checked the indicator stalk switch to ensure there's no short to the column:

IMG_8254.JPG

I've got a few spare fuses so have tried a 35amp & it blows as soon as you turn the key :( . I'll have to check for chafing as you say Colin but otherwise I'm a bit stumped.

Presumably there's a permanent short on that circuit at the moment because if it was switched at least the fuse would be OK until I used the brake pedal or indicator etc?
 
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A light bulb can go bad and cause a short, try removing the indicator and stop lamp bulbs and see if the fuse holds.
 
All those circuits mentioned are ignition controlled, did the fuse blow before or after a switching on the ignition
 
I would check the wire to the reverse light switch. I had mine go loose and short out against the tunnel.
 
That more or less rules out any weird back feed issues. Check the hazard flasher switch as it is prone to breaking the very thin plastic cage it all sits in.
 
Thanks so far guys.

I’ve disconnected the full dashboard, & brake light switch, but the fuse still blows when I switch the ignition on...
 
Looking at the wiring diagram I’m going to isolate everything connected to that fuse & see what happens when I turn the key.

If by a miracle the fuse is ok, I’ll then reconnect each item in turn.
 
Success! :D ....but try the simple things first.

After several evenings not getting anywhere, I decided to check for resistance (or not) between the positive feed & earth for each item off that fuse, on the basis that if my meter recorded no resistance then there would be a short somewhere. I looked at the wiring diagram & located the first item being the washer motor (which I hadn't isolated before...). I opened the bonnet & looked for the motor, which has been a replacement at some point:

IMG_8304.JPG

It was down below the inner wing area & you may have noticed the unprotected connector:

IMG_8303.JPG

I knew my luck was in & sure enough everything was working as it should :cool:. The motor is now securely fastened out of the way.

Today, however the temperature gauge has stopped working, so that's the next job.:rolleyes: At least the car is roadworthy again!
 
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