13 replies to this topic

[antcole]

Hello folks,

Have just finished my restoration, got it MOT'd and taxed in the last few days.

Completed less than 50 miles and then noticed the right hand indicator was stuck on and solid.

Then noticed the hazards wouldnt work, then noticed that when putting on the headlights, the right hand indicator stuck on solid.

 

Checked the fuses and found a couple blown plus the 15a in the inline fuses under the scuttle had blown too.

 

Didnt try new fuses but instead i went and searched for the cause, as its a brand new loom and fitted during the empty shell stage, with no heaving of wires through sharp holes etc.

The weird thing was i never noticed any smoke or smelled any burning at any time!

 

In the boot, i found the rear loom was melted solid and the drivers side earth wire (black) to the indicator cluster was loose, and had melted its plastic shrink wrap.

 

The most damaged wires were the red with thin green trace was completely exposed.

Tracked it further back and everywhere that colour combination ran, was melted and had burned through the PVC in several areas.

 

It looks like i will need to completely replace the entire loom.... :-(

 

I have a few questions....

 

1st, does anyone know what that colour wire is? Is it the main live for the whole car?

2nd, Has anyone had experience of this particular wire heating up and melting?

3rd, Can the rear loom be fitted without removing the headlining? Like pulled through if at all possible using the old loom?

4th, I have a large capacity (larger than original) alternator fitted, was a new unit from minispares, and could that have caused any issues - like too great a current output?

 

As you can imagine, im absolutely gutted and now face having to fork out another 300 quid for another loom.

My main worry is that it will happen again....

 

If anyone has some good experience on this, id be eternally grateful of any advice or wisdom.

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[Retroman]

Gutted

 

I think the red / green is indicators there is no main live as such other than battery cable to solenoid.

 

You can try pulling a new rear loom with the old I've done it, tape some individual wires and try not to make a lump

it helps with someone feeding it in, I have pulled front to back, the only snag is the interior light wires, which need fishing out

 

I don't see the alternator being the issue.

 

Get it checked out by an autolec maybe, you might have an answer as to why.

 

PM what looms you want I will get it to you at cost (about 20% off)

[Saint George]

The Green/Red (predominantly green) wire is the left hand indicator. The one in your photos that has fried is Red/Green (predominantly red). This is the tail light signal wire (both sides). I would say this wire has shorted to the earth wire at some point, possibly at a connector.

I doubt the alternator is at fault as it will only deliver whatever current the car demands and no more. Unfortunately the combination of a short circuit and a high current alternator will result in an awful lot of current flowing through this wire, hence the melted insulation. It could be that the tail light wire has fused to the indicator wire (Green/White for right hand side) as well, resulting in the indicator coming on with the tail lights. With this amount of current draw I would also check the brown wires going from the alternator to the starter motor for damage as well.

I have just had a similar issue on my City E but, as it was “only” the indicator wire which shorted to earth in my case it didn’t do nearly as much damage as yours has because the flasher unit meant it wasn’t a constant current flow.

I don’t know about pulling cables through the headlining I’m afraid but others on this forum should be able to help you with that.

[dyshipfakta]

Are the indicators themselves well earthed? They earth through the screws to the body shell at the front. It looks like they are finding earth elsewhere

[viz139]

It looks to me like you have posabley 3 different problems.

1. A short circuit in the rear right tail light. melted red and white wire . Blown fuse number 4 , possabley too large a fuse.

2. Right hand indicator became solid when earth to RH tail lights overheated . Check connector ,may need new spade.

3. Voltage dropping when headlights are turned on .Check voltage with a volt meter on front loom between green and black wires ( not the body), Probably bad earth connection on RH inner wing.

[Bat]

Hi,

Red green is side lights.

Should have been a 5 amp fuse on that probably 10a at most being a glass fuse.

Poor connection or a bad earth are possibilities.

Cheers 

[Saint George]

This should help

 

http://www.theminifo...agrams-redrawn/

[antcole]

Hello you lovely people.
Firstly, I'd like to thank you all for the replies, it's so appreciated and you've all offered such great assistance.

Right, I think I've found the problem....
Having looked along the whole route of that red/green wire, in the boot where it branches off to the offside rear lamp cluster, there is no damage to any of the wires.
So, tracked back to where the damage is and found the boot lid number plate light wiring was also totally melted.
Opened the light housing and found the first light in the line to have melted.
It then appears that the festoon bulb has dropped out and managed to contact with the live terminal and the aluminium housing.
There's a pin hole in the bulb cap and some burn/arc marks on the ally surface.

The fuse that I thought was blown wasn't actually blown... and has a strip inside it, which tells me it's a massive rated fuse.
Since I simply transferred the old fuses from the old wiring loom to the new one, keeping the old positions as found, I would imagine the fuses in the pre restoration mini were whatever the previous owner had.


I'm thinking the clear plastic lens has become hot and softened from the normal heat given off from the bulb.
That was enough to let the bulb drop out and rattle along into a dead short position on the housing..... with a massive fuse in the line, it was never going to blow.
I'll post up photos later to show what happened and where.

So.... herein lies a lesson for me.... don't buy p155 poor quality parts.... and make sure the right rated fuses are installed according to the system they're protecting.

The number plate lights are not genuine but the plastic that the terminals hook around should be able to withstand a lot of heat.
I would suggest making sure you check your fuses are correct if you've fitted non genuine rear number plate light lenses...!

A matter of a couple of quid very nearly cost me 5 years work and burned out my mini....

[Ethel]

It should really have blown a fuse. The festoon bulbs are bad, the interior light is also great at shorting. Not a bad idea to insulate potential short locations around the lights

[antcole]

You're right, a dead short should have blown the fuse, and it's strange to see that the fuse of that system was blackened and not blown, like it had been glowing.
The copper terminals had also got so hot that the spring tension was weakened.
Is it possible that a bad earth somewhere had caused an increased current flow?

[antcole]

....the fuse looks massive, with a metal strip inside, rather than a wire. Can't see what rating it is but I'd say 35a or greater.
I wish I'd thrown all the fuses and installed them according to the wiring diagram.... I'm not too good with wiring diagrams... :-(

Edited by antcole, 23 October 2018 - 02:16 PM.

[antcole]

Just a thank you and an update on this.... Andy at Retro Minis totally came to the rescue with supplying a new loom tailored to the car.
Very happy and satisfied with a total replacement rather than trying to repair the damaged loom.
Going to start pulling the damaged one out and painstakingly fitting the new one.
Many thanks to Andy and I will be ensuring the right fuses go on the right circuits from now On!

[cal844]

Just a thank you and an update on this.... Andy at Retro Minis totally came to the rescue with supplying a new loom tailored to the car.
Very happy and satisfied with a total replacement rather than trying to repair the damaged loom.
Going to start pulling the damaged one out and painstakingly fitting the new one.
Many thanks to Andy and I will be ensuring the right fuses go on the right circuits from now On!

There is a list of fuses and circuits covered along with the wiring colours for the fusebox in the FAQ section

Edited by cal844, 13 December 2018 - 09:12 PM.

[antcole]

Thanks cal. That's perfect.