12 replies to this topic

[Marky Tizz]

Model: Austin mini 30
Year: 1989
Description of problem (please be as in depth as possible):

Almost finished my car today ready for tuning and MOT tomorrow, but when we turned it around on the drive I realised there were no brake lights or reverse lights.
Checked the fusebox, fuse had blown, so we replaced it and it blew again.
went round and checked every single bulb on the circuit, all fine, all working, no shorts.
Checked the connections in the fusebox... then realised one wire wasn't connected properly, so connected it with a new fuse (which we had tested with everythign else and hadn't yet blown) and the fuse isntantly blew.
Traced this back to the aftermarket alarm unit that was fitted in 1991 (!), so spent our sweet time carefully removing it and the immobiliser from anything else that is part of the electrical system, including the indicators which it was wired in to flash.
This seems to have stopped the fuse blowing for now, but hasn't cured the problem. Now stuck at a completely loose end, as we can't find anything wrong with it.
Might also be worth noting the relay for the indicators doesn't even click.
Does anybody have any idea what is going on? All the other electrics in the car seem fine.

Please help me, I have the worst headache after spending the last 5 hours trying to work this out.

Many thanks

Mark



Any non-standard parts that might be involved with the problem?

Aftermarket alarm and immobiliser which have now been removed.

[taffy1967]

Well there's definitely something wrong with the top fuse circuit: -


Standard 4 fuse box mounted on the bulkhead: -


1 1-2 35amp Brake Lights, Reverse Lights, Direction Indicators & Rear Screen Demister.

2 3-4 25amp Horn, Headlamp Flasher, Brake Failure Circuit & Radio Memory.

3 5-6 25amp Heater Blower Motor, Windscreen Wipers, Washer Motor & Instruments.

4 7-8 15amp Side & Tail Lights & Panel Lights.


1-2 These circuits only operate with the ignition switch at position "II".

5-6 These circuits only operate with the ignition switch at position "I" or "II".

Is the fuse box new and in good shape?

[Marky Tizz]

Fuse box isn't new but it's in pretty good shape, I always try to keep it in good shape.

Fuse isn't dying immediately so that suggests to me it's outside of the fusebox.

Suggestions I've had so far

"a short to earth" - any ideas where? what on this circuit needs to go straight to the bulb/etc without being earthed?

Circuit not having an earth wire coming off the fusebox.

[taffy1967]

Well I've heard of owners whose fuse blows when they select reverse.

The problem was that the reverse light wires fitted to the selector shaft beneath the car were shorting against the exhaust.

So that's one possibility?

[Marky Tizz]

Sounds very possible, however, nothing works long before the fuse blows, and even leaving the reverse lights to the last thing to try, nothing works.

will have a look at it though.

Keep the suggestions coming people.

Cheers

Mark

[matt615]

This kind of problem is normally caused by a bad connection on the fuse box. You could try disconnecting the wires from either side of this fuse on the fuse box, and bridging them with a fuse and couple of bits of wire to by pass the fuse box. If everything now works then you know the fuse box is at fault, if not then you know you need to look elsewhere.

Obviously I'm just suggesting this as a way to narrow down the problem, not as a permanent solution.

[Marky Tizz]

Anymore ideas before i go to bed?

[stormintrooper]

This kind of problem is normally caused by a bad connection on the fuse box. You could try disconnecting the wires from either side of this fuse on the fuse box, and bridging them with a fuse and couple of bits of wire to by pass the fuse box. If everything now works then you know the fuse box is at fault, if not then you know you need to look elsewhere.

Obviously I'm just suggesting this as a way to narrow down the problem, not as a permanent solution.

i think he means make it into an inline fuse?

[mini-obsessive]

I had this problem with my mini a few months ago.. Fuse literally blew everytime i selected reverse or indicated.

I eventually found the problem with mine after pulling nearly every single wire. Underneath your carpet there is a wire running from behind the dash to by the handbrake.. im not that technical so dont ask me what it is for but i found that mine had corroded to just the wire and that was touching my body work and shorting the fuse all the time.. easy enough to check, just lift the carpet up in the front and locate the wire which u will find infront of gear stick. if this is the case then for MOT purposes u can just wrap the wire in electrical tape for the time being so that wire doesn't touch metal and them put a new fuse in... it worked for me

[Shifty]

This kind of problem is normally caused by a bad connection on the fuse box. You could try disconnecting the wires from either side of this fuse on the fuse box, and bridging them with a fuse and couple of bits of wire to by pass the fuse box. If everything now works then you know the fuse box is at fault, if not then you know you need to look elsewhere.

Obviously I'm just suggesting this as a way to narrow down the problem, not as a permanent solution.

Didn't read correctly, sorry.

Edited by shiftyseamus, 05 January 2009 - 11:12 AM.

[Marky Tizz]

Fixed it!

Reverse light switch was shorting on the new exhaust... just disconnected it for now, will be moving the exhaust tomorrow.

Mark

[taffy1967]

Fixed it!

Reverse light switch was shorting on the new exhaust... just disconnected it for now, will be moving the exhaust tomorrow.

Mark

So I was right? Excellent!

[Marky Tizz]

Well I've heard of owners whose fuse blows when they select reverse.

The problem was that the reverse light wires fitted to the selector shaft beneath the car were shorting against the exhaust.

So that's one possibility?

Yes, you were taffy

Thankyou so much for your help.

Mark