17 replies to this topic

[cal844]

hi guys, 

 

my 1993 mini keeps blowing the top fuse, 

 

went a short drive to the shop, everthing was fine, started the car up, indicated to pull away... no indicators :/

i know for definate it isnt water getting in the lenses as they are well sealed, 

 

 

HELP

Edited by cal844, 27 January 2014 - 12:54 PM.

[tiger99]

Like all such problems it could be anywhere in the wiring of the affected circuits, obviously a short to earth. Water alone usually does not have sufficient conductivity to blow the fuse, but you have already ruled that out anyway.

 

You could start by checking the wires near to the indicator switch for chafing or abrasion. Dies it blow immmediately, or only when you indicate? If only when you indicate, check at the bunch of bullet connectors, front and rear. And, on your model, what else is on that fuse? Brake lights, for example? It is not uncommon to have chafed wiring at the pedal switch. And, the reverse lamp may be on that circuit, its switch is in a vulnerable position, and it is common to find that the wires have become displaced and melted on the exhaust pipe. If several circuits run off that fuse, which is not unusual, you can disconnect all the outgoing wires from the fusebox terminal, and put them back one at a time until it blows, then you have narrowed it down to one circuit.

 

Unfortunately I can't find my CD with the manuals and wiring diagrams right now, or I could be more specific.

[cal844]

it is an intermittant fault, its been ok for about 3 weeks and now its cropped up again

[tiger99]

Intermittent faults are always difficult. You could run a wire from the fuse, to a small 12V lamp in the cockpit, so that you know immediately that it has blown (lamp goes off), and so be able to relate that to exactly what you just did, for example which switch you operated, or perhaps some heavy acceleration or braking. That may help to pin down the location of the fault.

[cal844]

i just use the rear window demist tell tale light 

[KernowCooper]

Fuse 1 on a 4 4 box is 35amp and supplies stop lights, reversing lights, direction indicators, heated rear window, being intermittent is as tiger99 has pointed out is a lot harder to find, if it does it every time a fuse is inserted then you can remove with individual wires and indentify which of the 4 is going to ground. If you use the rear window tell tale light surely this means driving around with the heated rear window on all the time? better to fit a bulb as less current draw, and better than having the rear window drawing a fair bit of current.

 

Visual checks once you've found the circuit, but intermittent one are never easy, I would move around the loom moving wires with the bulb connected between the fused dide of the fuse and earth, move wires and watch for the bulb going out and thats your problem area, its the way I do it but I use my sealey tester which does exactly the same job.

Edited by KernowCooper, 28 January 2014 - 12:10 PM.

[cal844]

i'll ask my mate to come down at the weekend, me my dad and my mate will find the problem.. i'll just need to keep looking :)

[cal844]

id checked the wiring for signs of damage to the insulation, i found 2 wires which had splits in the insulation, we covered them with insulation tape to see if it eliminated them... it didnt, so my mate came down on saturday and we found that the engine bay earth(left of the brake servo as viewed from the front of car) was faulty (corrosion) so i cleaned it up and its been fine since!!

[cal844]

d'oh this car is really starting to annoy me! ive traced the fault to the LHS indicator, i'm going to try swapping the indicator and windscreen stalks over from my dads project to see if this will solve the problem...

 

to be continued

[tiger99]

The indicator circuit can fairly easily short to earth at 3 places, the horrid bunch of bullet connectors behind the top of the grille, the almost as horrid bunch of bullet connectors in the boot, or, if fitted, the side repeater lamp.

[cal844]

thanks tiger99, i'll double check these tomorrow.. i have changed the stalk for a spare from my dads italian job project (its been very handy!!)

[KernowCooper]

be very surprised if swapping the switch the switch is the fault, in the actual switch contacts on the indicator circuit there is only a central 12v in and out to L/R Indicators and the assembly is plastic and unless the connector or insulation is split is shorting then its somewhere else going to earth. I'd be rechecking all those points tiger pointed out above.

[cal844]

changed the switch and made it worse!! this morning in the rain it blew 6 fuses to do a mile.... so i'll change it back and see from there

[tiger99]

You are probably now at the point where you need to look for split insulation or other damage in the wiring. It could be just about anywhere, in the green-red circuit, if it is definitely associated with left indicators. The wire starts at the indicator switch, and splits somewhere, depending on model and year, at a bullet connector, one run going to the front indicator via the bullets behind the grille, the other runs to the boot, where a bullet joins it to the wire from the tail light cluster. A third branch runs to the warning light on the dashboard. It also goes to a terminal on the hazard switch. There is also the side repeater, if fitted. As you can see, a large part of the wiring run is inaccessible, in the roof and pillar area, or behind the fuel tank, but wiring damage is most likely in the under-bonnet area.

 

Just had a thought, has any work been done on the car recently, before the problem started? I am thinking about welding work on the nearside, particularly the A pillar.

[cal844]

the car is a 1993 spi shell, with HiF 38 carb feeding a 1275 engine  from the factory...

 

there was welding done ages ago, the only welding on the nearside was to block off the fresh air inlet, but there is no wiring damage as this was checked before it was rebuilt..... went out to the crar when my dad got up, put a new fuse in it and its been fine since!!!!

 

really is frustrating me!

Edited by cal844, 05 February 2014 - 06:04 PM.