Classic cars forum & vehicle restoration.

[SloResto]

I've had a bit of a break from restoring but now with my weekends back am throwing myself back into the fray.

I'm just looking at the wiring harness on my 51 Ph 1 Vanguard and wondering where to next? There is a fault when you pull the light switch fully out.. That is, in its first position the parking and instrument lights are OK but when you try the headlamps the wires at the switch start to burn.

I've replaced the five wires from the switch some of which go to the floor dimmer switch but the problem persists.

Also, just looking under the right front guard I see a wire to the headlamp that has lost its insulation in places and needs replacing. Similarly a run of cables adjacent to the fusebox looks pretty ordinary... however other sections of the harness look OK and its obvious the previous owner has done some work on it.

I dont want to go to the expense and hassle of renewing the entire harness but repair it the best I can and hopefully it will be OK. I will look to replace the roll of 10 or so wires behind the fuse box and use some multi-connectors where possible.

Is this a viable approach or can anyone suggest otherwise? Thanks in advance.

[peter scott]

Yes, it is a viable approach. I guess it's stating the obvious to suggest that you should carefully examine the whole loom for further potential insulation failures though.

Peter
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http://www.nostalgiatech.co.uk
1939 SS Jaguar 2 1/2 litre saloon

[SloResto]

Thanks Peter. I'm not great on electrics and do struggle. Thing is with the colour coded wiring - the colours were food dye and have faded to all pretty much resemble each other... but will soldier on.

The old Vanguard is going but yet to take it out of the garage as have just taken off all my brake lines to get them double flared.

In the interim i hope to sort out the electrics so I can restart work on the other cars. BTW I love the 47 Jag - very elegant lady and oozing with charm. Was the 49 model much changed from the 47?

[PAUL BEAUMONT]

I have had dealings with Autosparks in the past. They manufacture replacement looms in the correct colours. It might be a plan to investigate the cost of a full or even part loom from them and then use only as much of it as you need. I appreciate that a complete rewire is a challenge on a nicely upholstered saloon. The partial rewire, possibly using period looking bullet connectors could well be a cost effective simple solution.
I know of the problem of faded wiring colours, but if you trace the lines withing the cotton shroud or whatever until you come to clean cable that has not been exposed to the elements you usually find that the colours are reasonable.
If all else fails, invest in a fire extinguisher!!
Good luck
PAUL

[Greeney in France]

I managed to completely renew my own Traction Loom It took me a week while my wife was in the UK I moved the sofa and chairs around the edge of the room and remade it on the lounge floor using the floorboard joins to put pins in to hold it. Its not difficult just might give you a headache from concentrating so hard
I got all the parts from here;
http://www.vehicle-wiring-products.eu/VWP-onlinestore/home/homepage.php

Well worth doing though if you can be methodical
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www.OldFrenchCars.com

We do these things not to escape life but to prevent life escaping us

[Glenn Crawford]

You probably don't need t be told this, but... make sure you renew all the rubber grommets where the loom passes through steel bulkheads; and if the loom is attached to the car using steel "P" or spring clips, detach each one and check the insulation beneath it. I suspect that most electrical fires in old vehicles come not from short-circuits between wires but from cracks in chafed or brittle insulation allowing the wire to touch the car's body or chassis.

A couple of years ago I heard of a totally original pre-war Riley Nine which was totally gutted by fire in just a couple of minutes. The fire started while the owner was driving it but the red-hot loom was such a big heat source that he could do nothing except park, evacuate the car, and watch as it was destroyed befoere his eyes.

Sorry to be gloomy - but you're doing the right thing in sorting out your wiring, don't miss anything out!

[SloResto]

Thanks guys for the advice - will proceed with caution and one hand on the fire extinguisher!

I get the impression that alot of restoreres replace wiring looms as a matter of course and was interested at which point does one decide to go with a new loom.

From your replies it seems that such a decision is subjective based on the condition of the loom.... one man's trash can be aanother mans treasure.

[Phil - Nottingham]

Its a contant source of amazement to me of the state of some wiring looms I see at car rallies. Shiny/immaculate bodywork and interior and polished rocker covers etc but with oil soaked/frayed/taped fabric covered wiring that passed its use by date 30 years ago.

Domestic wiring in old vulcanised rubber or paper/lead insulation was being condemed in the 1960's and even "modern" PVC stuff may well be past it in less than 25 years.

Most classics up to the early 1970's had bsiaccly simple wiring so tehre is really no excuse for not rewiring eitehr by buying aloom or the materails to DIY which places like Vehicle Wiring Products sell
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Rover P2
Rover P4
Rover P5 & P5B
Land Rover S2 & S3
Morris Mini Traveller Mk2

[Glenn Crawford]

Phil is right, there is no excuse in not renewing the loom if you're doing a restoration, or if the loom is getting past it. But it's not automatic and as "SloResto" suggests, the decision when to replace it is subjective.

I recently bought a 1949 car in nice, original, unspoilt condition, with wiring to match. Yes, the insulation will be brittle and yes, the rubber grommets are getting tired, but I know that if I'm careful and don't go bending the loom about during maintenance that it will continue to do its job safely. But I'll replace it any part of it that becomes potentially unsafe, because although the joy of my mobile time-capsule is that it has not been restored, there's no point in taking it to the extreme where there's a risk of it being destroyed by its own originality.

[DM]

SloResto,

Rather than risk burning out your wiring harness with that type of electrical fault, why not put a healamp bulb (with both filaments connected in parallel) in line with one of the battery leads.
This will limit the current to a safe level while you fault find.

DM