I've made a mistake somewhere

[Colin Lindsay]

Autosparks are £245 for a complete Mk1 loom; you could make contact and see if they'll do the front part only. https://www.autosparks.co.uk/catalogsearch/result/?q=triumph+spitfire

Second-hand... depends on who you buy from. Old looms can be brittle and end up causing bother.

Chris' remark above about the purple wires brings me to the Herald loom, where there's a purple wire from the horn push that goes to a brown wire at the first connection, near the steering column; the headlamp flasher is brown but goes to a purple cable at the same junction. If the early Spitfire (from the same era) is the same, make sure you haven't simply connected colour to colour as this may explain the duff headlamps.

[Josef]

Autosparks make to order, and will customise with alternator connections etc so I would expect they’d have no trouble supplying just the front half. But check the rear wiring isn’t in as bad a state first! 

[Neil Clark]

Although it was a front end smash so the rear could be OK, I suspect that modifying the standard loom will cost as much as a full loom!  Their phone is constantly busy today - and TD Fitchett recommend Autosparks, Canley buy them in 12 - 16 weeks, Moss are on back order 3 -4 months - sounds like could be a 12 week wait!

[DanMi]

you could first try stripping out the added bits and see what state the loom is in, it may well be recoverable, if they have simply added bits with connectors and scotchblocks and there is no burnt out wires which will be obvious as the tape will have melted.

 

 

[Neil Clark]

At least I can take the dash board off and make up a loom of my own using the "new" professionally made loom with the existing instruments, and hopefully with the correct colour wires.  The instruments all seem OK.  It's all spade connectors and bullets and I have plenty of those.

I'm still confused by the difference between control boxes and relays.  I have an alternator and I thought alternators needed relays as well?

[NonMember]

1 hour ago, Neil Clark said:

I suspect that modifying the standard loom will cost as much as a full loom!

What mods do you need, beyond the alternator? That's a standard option mod from AutoSparks, adds about £50. I had them add headlight relays to my Mk3 loom (located for mounting on the radiator support) as well as connectors for a custom electric fan controller and inertia switch for my electric fuel pump.

However, the standard product is the two piece full loom - front part covers engine bay and dash area, rear part is much simpler. Whether they'll discount you much for not having that rear part... I couldn't say. There is no intermediate connector between dash and engine bay on the standard loom, so any attempt to replace only part of that is likely to bump costs.

[NonMember]

Just now, Neil Clark said:

I'm still confused by the difference between control boxes and relays.  I have an alternator and I thought alternators needed relays as well?

There is no connection between control boxes and relays. Nor between alternators and relays. They do completely different things.

A "dynamo control box" is a form of voltage regulator, built using electromechanical techniques that bear some resemblance to how relays work. There are usually two or three relay-like-things in a control box.

Alternators have a diode rectifier pack and a solid-state regulator, usually both built in to the alternator. They therefore don't need an external "control box" because all the voltage regulation is done inside (and with transistors instead of things-that-aren't-actually-relays).

A relay is an electromechanical servo device. It has a coil and some contacts. The contacts are just a switch, nothing more, nothing less, but operated by the magnetic field from the coil. So when you pass a small current through the coil, the switch closes allowing a BIG current to flow in the other circuit. You would use one whenever you need to switch something hefty with something weak. For example, main beam headlights with a column stalk. Or a D-type overdrive (20A pull-in) with a column stalk. This has nothing to do with alternators or dynamos or control boxes.

[Neil Clark]

Thank you.  An alternator does away with the need for a control box.  

If I was to make a partial loom myself to replace the mess behind the dash, using the wiring loom in the manual, would I need the relay to deal with the issue of the dip / main / flash column stalk handling the headlight voltage?

[Neil Clark]

- If I was to make a partial loom myself to replace the mess behind the dash, using the wiring loom in the manual, would I need the relay to deal with the issue of the dip / main / flash column stalk handling the headlight voltage?  Do you know if there anything else I would need to have that is not in the Mark 1 wiring drawing?

[NonMember]

If you're going to add a relay for the headlights, and if you want it to actually do something useful, then you DO NOT want to put it behind the dash. The optimum location for such a relay is somewhere between the alternator and the bonnet connections - hence my choice of mounting them (to do the job properly, you want two - one for main and one for dip) on the radiator support frame. So no, in terms of what you are building behind the dash, you don't need to include the relay. Just follow the manual.

As to other things, unless you've got "features" that weren't standard on the Mk1 (such as hazard flashers or modern stereo) then just do exactly as the WSM wiring diagram shows. If you do have any add-ons (Pete's "must haves"?) then let us know what they are and we'll advise on loom changes needed.

[Colin Lindsay]

30 minutes ago, Neil Clark said:

Thank you.  An alternator does away with the need for a control box.  

If I was to make a partial loom myself to replace the mess behind the dash, using the wiring loom in the manual, would I need the relay to deal with the issue of the dip / main / flash column stalk handling the headlight voltage?

Nope; no relay in the original loom so no need for one now, even with uprated headlamp bulbs. Don't overthink the existing loom too much; it's simple. Just follow along the dash and match each component with the wires it's meant to have; it all falls into place quite easily.

[Josef]

For something like a stereo, or anything else that doesn’t absolutely have to modify the stock wiring, my preference is to build a smaller sub loom. That way it’s easily removable by you or any future owner, and would help avoid any future difficulties such as you are currently having yourself!

[Neil Clark]

I can't thank you all enough for the help this week.

[Colin Lindsay]

10 minutes ago, Neil Clark said:

I can't thank you all enough for the help this week.

I'll bet most of us wish we were there to help sort it out. It would be so much easier than trying to work remotely!

[Neil Clark]

I went over to our local motor factors for multiple colours of wire.  We've known each other for decades.  "Here you are he says, take these reels, pay me for what you use when you bring it back."

[DanMi]

At this stage I would not consider adding new wiring, I would take the existing back to standard and get things working, before considering anything new. If the loom is damaged probably better to replace than repair. Rimmers appear to have a MK2 in stock and the only possible difference that I can think of would be a longer temperature sensor wire as they moved it's location, though there could be other minor differences.

[Neil Clark]

I've spent the afternoon cutting out the extraneous wiring and making sure that all the routes and the connections were correct.  It was made very complicated because the wiring diagram, the loom used and of course the PO's modifications each used different colours in many parts.  I've taken the switch covers off the column switches and think they all link up.  

The red wire from the inline fuse goes only to the PO's relay and has no connection with the lights at all, only the horn wiring.  The two purple wires on the horn circuit seem fine but there is one random purple wire with a bullet on the end sticking out.  I can't get a circuit on that bullet so have just covered it with tape for tonight.  All the switch circuits and switches seem to be live.

It may be that I'll find something tomorrow.  If I can get the headlights to work I'll have to tidy up all the connections.  Apart from the blue snap connectors some of the bullet connectors were not properly engaged in any places and loose.  However I still managed to create circuits.

Other than the loose wire short circuit that must have blown the fuse (which I've now found and cleaned up temporarily) I'm still not there.  Will check again the earths on the bulkhead tomorrow because it's all I can see may be wrong.  I charged the battery a few days ago and the built in telltale says it's fine but I'll get it tested.  It's dropped to 11.5V already.

I'll have to copy and tippex the wiring diagram to update the wire colours for future reference.

[Neil Clark]

Finally got power to the headlights and they work main and dip using the new switch I had bought.  No flash function nor dashboard lights but the main problem is seemingly fixed.  For sanity I tried them with the old switch which promptly started smoking which may explain the pop fizz blown fuse when I first switched both the side and headlights on.  They had worked on the old switch individually before - could that have been load as an issue?

[DanMi]

The instrument lights are the red/white wire, which should go to position 8 on the main switch (according to the workshop manual) and activate on the second click plus you need a good earth between the instruments plugged into a loom earth. To get the flash function the wire should come from the inline fuse via a brown/black in the loom to the column switch. the switch going could have been due to a short somewhere.

[DanMi]

I will try to explain control box/relay

 

The control box is to make the dynamo work, the dynamo is a spinning coil within an electromagnet. In order to generate current the electromagnet needs power, but too much will cause the voltage to go too high. The control box switches the current to the electromagnets on and off to keep the correct output voltage. The same functionality is built into an alternator.

 

A relay is an electric switch with a low power side, connected to the switch on the dash, and a high power side connected to the load eg horns. when you push the horn this puts a voltage across the low power side of the relay which activates the switch to make the horn work, the point being that the high power does not go through the horn push/switch

 

The voltage regulator (near the flasher unit) is there to keep the voltage to the fuel/ temperature gauge at 10 volts so that the instruments are accurate. The original just switches the current on and off to average 10v the new black box is probably solid state and will maintain a constant 10v

[Neil Clark]

Thanks -I'm clear now on alternator / dynamo / control box.  And the instruments (fuel / temp) are accurate as far as I can tell after running the car for 20 minutes.

I'll work on the dashboard lights and flash functions next, probably tomorrow now.  The in line fuse wire only goes to the horn relay so need to look at that.  

[DanMi]

This is the in-line fuse for the horns beside the starter solenoid. What has the PO been up to? Plus the Horn Relay should be on the battery box/bulkhead strengthener just behind it not in the cabin and that is the only relay originally present unless you have overdrive

[DanMi]

horn relay with the purple wires, the other one with the home made wiring is the overdrive relay on my car

[Neil Clark]

On my headlight column switch now with the dashboard switch to "headlights on", dip is the mid position and main is the down position.  Up seems to do nothing.  I don't have a transfer / label on the housing next to the lever so I'm not sure.  I can see on the wiring diagram that there should be a connection to operate the "flash".  

I have no evidence that the PO ever had this function working / connected to the headlights due to the crash damage to the lights themselves.  However before I got the lights to work yesterday the blue mainbeam telltale lamp illuminated if the column lever was in the mid and bottom position.  

With the confusing mix of wiring colours in the car I seem to have 5 wires to the column switch.  The photo of the new Moss dashboard switch is taken from the bottom - Moss have no wiring diagram for this switch.  The paired Red / Green (looks black) has two spades available.  Any thoughts on the one I'm using?

[DanMi]

Up should be sidelights only middle main and down dipped. So in fact the up does not make any connection

brown is unswitched +ve

red/white is for the instrument lights

red/green 1 wire goes to the sidelights the other to the column switch

the workshop manual says for the main switch brown position 4 red/green 7 and red/white 8 but can't remember if the switch actually has numbers on it

The flash function is powered independently, from he inline fuse by the flasher unit which the PO seems to have used for the horns (for some unknown reason) via a Brown/black wire in the loom which will probably be unconnected near the inline fuse

The blue tell should only light with main beam so no idea what is going on there

 

for the column switch blue/white is dipped blue/red is main, the wiring diagram says brown/red is the power feed so goes into the red/green from the main switch and brown/black is the power feed to the flash which connects to the brown black from the inline fuse.

 

The wiring colours you have are exactly as they wiring diagram as far as I can see