Numpty about to attempt rewire

[david c]

Well I have bought a new wiring harness,

I have the inner dashboard out, actually I have everything out except the old harness which I have labeled up in best masking tape and biro, (soon learned that pencil is no good, sort of rubs off just when you need it)

I would be very grateful for any advise or tips before I get started on what is for me the most daunting part of the restoration, I hate electrics and have very limited knowledge of the subtleties, on the plus side I do have time and patience.

Harness bought from TR Shop.

Also while I am on any tips on remaking plenum chamber outlet pipe, mine is still in the rubber hose, in a manor of speaking.

 

[RogerH]

Hi David,

somebody posted an excellent tip for the harness.

Instead of simply pulling the wiring connections off the gauges etc, cut them off and leave a good 2" of colour coded wire showing.

 

Regarding the plenum drains get them sorted before before the rewire - extra space to work in.

 

Roger

[bob-menhennett]

David

You've made a good start by labelling. Take photos of the existing loom in situ ...so that you know the route and what size rubber grommets are placed where.

You did order some new grommets of course ?

Some people recommend cutting off the old wires to the equipment, leaving 2" / 50mm still attached, so you can marry up the correct colours when installing the new loom.

You will find numerous metal tangs around the body shell retaining the wiring loom in situ. Bend back the tangs carefully and " just " sufficiently to release the loom.If the rubber sleeve protectors are past their sell by date, replace or use shrink wrap tubing cut to size. DON'T bend back the tangs until the whole loom ( New one ) is in place. It will leave you some " wriggle room " , if the connectors are just a tad short of the equipment and you need a bit of push / pull to get it to fit.

 

Getting a coloured wiring diagram blown up to a A5 size ( that is the bigger size isn't it ? ) is a good investment. Make notes, if the loom differs in any way, so you have a record for future electrical fault finding.

 

It's easiest pulling the engine bay part of the loom, back into the cabin.Either roll this section up and / or put it in a plastic bag to keep it tidy.

Do the same with the rear part of the loom, lights , fuel sender etc.

Overdrive (? ) wiring next, if fitted.

Then concentrate on the back of the dash stuff.

Lay out the new and the old loom ( on the lawn / garage floor ) to check that you have the right new loom...otherwise guess whose got to take out the new one to return to the supplier ?

Put the whole of the old loom in a big plastic bag but retain for reference purposes, if needed.

 

Clean every terminal on the equipment mercilessly until you have bright clean metal for a good electrical contact.

Fit the right size grommets onto the new loom , if you want to or as you go along.Carefully feed the loom through the relevant bodyworks holes.

 

Work you way through the car methodically.I found it useful to temporarily bundle up wires together with cable ties to keep things neat and tidy.

Fit shrink wrap to the wires before connecting up , if necessary.

 

If you've order extra fittings for " new " equipment, alternator, fan,electrical windscreen washer , etc then choose the tidiest route, keeping the wiring away from moving objects or heat sources.

Replace the battery and body earth straps if required and get the battery fully charged up.Looms don't normally come with a new lead... coil to distributor so replace that if suspect.

 

Repair / renovate wiper boxes and heater set up whilst you have good access..you don't want to have to do it later when it's all back together !

 

Just take your time and don't rush at it. Good luck with it.

Bob

Edited April 6, 2015 by bob-menhennett

[Geko]

Hi,

1/ some forumnites puzzled over which side should the harness fit. On 4As, the wiring harness fits on the right side of the car contradictory to the MOSS catalogue schematic (see attachment);

2/ Get a wiring diagram (see attachment) and tag the wires once the harness has been installed

3/ If you haven't done it yet, do foresee extra wiring and relays for upgraded electrical equipment. While thinking about it you'd be surprised how many you will need - fan, fuel pump, fog lamps, gauges, radio speakers, reverse light, etc....

 

 

 

[RogerH]

I think Bob meant A3

 

Roger

[stuart]

Buy a load of new Lucar connectors as well as the new loom doesnt come with them. Mostly singles though you will need a few doubles. Its always worth replacing as its a difficult job cleaning the old ones up sufficiently.

Stuart.

[RogerH]

Hi Stef,

my 62' (CT6272) TR4 has the wiring harness on the righthand side - not as shown in your pic

 

Roger

[MRG1965]

David

You've made a good start by labelling. Take photos of the existing loom in situ ...so that you know the route and what size rubber grommets are placed where.

You did order some new grommets of course ?

Some people recommend cutting off the old wires to the equipment, leaving 2" / 50mm still attached, so you can marry up the correct colours when installing the new loom.

You will find numerous metal tangs around the body shell retaining the wiring loom in situ. Bend back the tangs carefully and " just " sufficiently to release the loom.If the rubber sleeve protectors are past their sell by date, replace or use shrink wrap tubing cut to size. DON'T bend back the tangs until the whole loom ( New one ) is in place. It will leave you some " wriggle room " , if the connectors are just a tad short of the equipment and you need a bit of push / pull to get it to fit.

 

Getting a coloured wiring diagram blown up to a A5 size ( that is the bigger size isn't it ? ) is a good investment. Make notes, if the loom differs in any way, so you have a record for future electrical fault finding.

 

It's easiest pulling the engine bay part of the loom, back into the cabin.Either roll this section up and / or put it in a plastic bag to keep it tidy.

Do the same with the rear part of the loom, lights , fuel sender etc.

Overdrive (? ) wiring next, if fitted.

Then concentrate on the back of the dash stuff.

Lay out the new and the old loom ( on the lawn / garage floor ) to check that you have the right new loom...otherwise guess whose got to take out the new one to return to the supplier ?

Put the whole of the old loom in a big plastic bag but retain for reference purposes, if needed.

 

Clean every terminal on the equipment mercilessly until you have bright clean metal for a good electrical contact.

Fit the right size grommets onto the new loom , if you want to or as you go along.Carefully feed the loom through the relevant bodyworks holes.

 

Work you way through the car methodically.I found it useful to temporarily bundle up wires together with cable ties to keep things neat and tidy.

Fit shrink wrap to the wires before connecting up , if necessary.

 

If you've order extra fittings for " new " equipment, alternator, fan,electrical windscreen washer , etc then choose the tidiest route, keeping the wiring away from moving objects or heat sources.

Replace the battery and body earth straps if required and get the battery fully charged up.Looms don't normally come with a new lead... coil to distributor so replace that if suspect.

 

Repair / renovate wiper boxes and heater set up whilst you have good access..you don't want to have to do it later when it's all back together !

 

Just take your time and don't rush at it. Good luck with it.

Bob

Hi Bob I think you mean A3, A5 is the size of a large post card.

A0 would be best if you have access a large plotter.

 

Mark

 

Mark

Edited April 6, 2015 by MRG1965

[david c]

Every bit of advise a "nugget" I Like the sound of leaving a little cable still attached to help Identification, simple and cheep, bit like me really.

Ah yes new grommets......bu***r, still it's going to take a while to fix the drain, one side only thankfully, must have been parked on a slope (can I say that?)

Tinker about with the wiper stuff and the heater........bet I shouldn't say tinker either. Shakespeare never had these problems!

and order a bucket full of Lucar connectors.

No intention of trying to start the old girl yet, just trying to do stuff while the opportunity presents it's self.

Thank you all for your advise and diagrams.

[stuart]

Hi Stef,

my 62' (CT6272) TR4 has the wiring harness on the righthand side - not as shown in your pic

 

Roger

They all do Roger if you look at Stephs pic thats what the red lines on the right hand one illustrate, only variation is on very early 4`s that the loom goes over the top of the front right hand wheel arch instead of round the inside of it like the later ones.

Stuart.

[bob-menhennett]

Roger / Mark

Of course it was A3 , I knew that !! Thanks guys for helping me out... I'm suffering with brain fade at the moment.

Bob

[Grahamgl]

Hi David,

 

I would recommend that you buy some terminal covers for the Lucar connectors and, make sure you buy the connectors to suit the size of cable you are going to fit them to. Also solder the cable/lucar joints, don't just rely on crimping them. Don't forget to smear the male Lucar connectors with vaseline before connecting the female ones, this helps to resist corrosion..

 

Here is a link to the company that I bought all mine from: http://www.polevolt.co.uk/acatalog/6.3mm_Terminals.html

 

Regards

Graham

[peejay4A]

Put a bit of heatshrink on the ammeter fixing bracket. I've never liked how close it runs to the terminals. If something metallic drops between a terminal and the bracket you've got a fire.

Edited April 7, 2015 by peejay4A

[Motorsport Mickey]

Every bit of advise a "nugget" I Like the sound of leaving a little cable still attached to help Identification, simple and cheep, bit like me really.

Ah yes new grommets......bu***r, still it's going to take a while to fix the drain, one side only thankfully, must have been parked on a slope (can I say that?)

Tinker about with the wiper stuff and the heater........bet I shouldn't say tinker either. Shakespeare never had these problems!

and order a bucket full of Lucar connectors.

No intention of trying to start the old girl yet, just trying to do stuff while the opportunity presents it's self.

Thank you all for your advise and diagrams.

 

Just wait until you start to post about male and female Spades !

 

Mick Richards

[EdwinTiben]

On of the advantages of a (good quality) harnass is that all the color should be "by the book".

 

I used the wiring diagrams from this site, printed it out and had this next to the car.

 

http://www.advanceautowire.com/tr24a.pdf

[RogerH]

Hi Stuart,

one day I really will understand what I'm looking at (or perhaps it's a bit late).

 

Roger

[tthomson]

Get a bunch of tie wraps of differing sizes. It is amazing how useful these are when rewiring.

 

TT

[mleadbeater]

Hi David, here's my advice 4WIW,

 

firstly get a copy of the Haynes 'Automibile Electrical Manual', assuming its still in print, ( although an older one may be better for our era of car, mine is dated 1983,) some used copies may be around on Ebay, a really usefull book for basic and advanced car electrical info. It covers basic electrical theory thro to harnesses, switches, connectors, cable sizes, tools etc.

 

secondly get a good wire-cutter/stripper, the automatic type are good, plus a decent crimper tool, plus proper conectors, Vehicle Wiring Products are a good supplier of all these., and a soldering iron, I like the gas type as fast warmup, I am waiting for Aldi to stock them again as mine packed up after 5 yrs.

 

Also get an assortment of sizes of heat-shrink tube, use an electric paint stripper to shrink.

 

Apart from the voltage regulator, which is a bit complex to understand, the wiring is simple if you think of every device on the car,( lamps, motors, etc) as needing a 12v feed from the battery, ususlly via a fuse, switch, or whatever, then earthed to provide the return circuit.

 

Device wiring has standard colours ( on UK cars from pre-war well past the age of our TR's), for example ( not fully )

 

Brown = main power feed from battery, ammater, voltage control box,

Blue, combined with red or white= headlamp circuit, dipswitch, light switch etc

Red= sidelight circuits, front/rear, panel lights

Purple= horn circuit, (not fed through the ignition switch)

Green, combined with other colours=auxilory circuits, indicators, wiper motor, brake light & switch, fuel gauge etc

White=ignition circuit, coil, and combined with other colours = fuel pump, starter solenoid, coil,

Black=earth connections ie.to body or chassis

 

for some devices, eg lights, there is no fuse, auxiliary devices are usually fused.

the ignition switch controls lots of other devices only powered when ignition is on, again not fused.

 

 

 

some devices have a switch in the supply, eg wipers, others have a switch in the earth connection, eg heater or electric fan if fitted, the diagram shows which have what.

never sure why but there it is.

 

Just follow the daigram colours and mark up with a label each end once you have identified each wire, the run of the cables will soon become obvious.

 

Hope this helps rather than confuses, you'll get the hang of it after wiring 3 or 4 cars.

 

good luck

 

Mike

[david c]

Thats interesting, I didn't know that.

I Think I may have that Haynes guide somewhere, I have now stripped out the old loom and lots odd bits of cable, ordered shrink sleeving, heaps of new connectors, grommets and cable ties.

Have spent the last X months moving bits of the loom out of the way of what ever I happen to be doing, Its quite a relief to have the old stuff out of the way, and it does make the interior look much tidier.So now its onwards with priming painting seam sealing and more painting the bits I hope I never have to get to again.

Thanks all for your help and encouragement.

 

 

David

 

(wish I'd thought this through before I started, would have specified extra wires for electric fan,spot lights etc)

[mleadbeater]

I just remembered I only fitted one horn to my '2, and used the O/S horn feed as a supply to an electric fan, not sure if this applies to a '4

 

May help

 

Mike