MK1 Wiring Loom

[Andy Borris]

Need a new wiring loom for MK1 with an alternator and (hopefully) headlight relays, any recommendations?

Thanks

Andy

[mikeyb]

buy the cable online and splice it into your existing one yourself.  plenty on here that have done just this!

you won't be able to buy such a loom off the shelf.

Saloons never came with headlamp relays, so this will be a new install - either make a new loom that is triggered from one of the existing headlamp plugs or cut and splice into the runs to the headlamps down each chassis rail under the bonnet.

I did the former my mk2, the latter on my Sprint. The former has the advantage of being "non-damaging and non-invasive" but uses a lot more cable length, the latter is a lot neater but involves cutting into the main loom.

We did an alternator conversion on Gertie our old Mk1 (now owned by Radders and still in my avatar!).  We used the existing dynamo connections straight into the back of the alt if I remember correctly, and ran an extra power wire back form the alt to the solonoid.

[James]

You can easily relay the headlights on a Mk1 by disconnecting the bullets behind the fuse box on the passenger side in the engine bay.

No need to cut any wires at all.

[piman]

Hello Andy,

if you really need a new loom and have it tailor made, Auto Sparks should be able to do that. http://www.autosparks.co.uk/

Alec

[Andy Borris]

The car has already got an alternator conversion and relays, however I've found melted wires in the loom, so I'm thinking a fresh start may be easier (and safer) then repairing.

I think I've already emailed Autosparks, have you used them?

Andy

[DJB_Harvey]

Autosparks are an excellent firm and are very familiar with Mk1 looms and upgrades . They have had a lot of looms off me in the past to copy for reference purposes .

[dazzer]

Yes Autosparks are very good. I seem to remember the looms come in two pieces which is joined near the bulkhead.

[Andy Borris]

My wiring is a mess, but not quite as bad as I first thought!

Car now has a 2 wire Bosch alternator, with a large cable running to the battery and a second much thinner wire, this is (I'm assuming!) the field wire?

Can I use this field wire to power the ignition light?

Secondly, the Brown/White wire from the dynamo control box, this provides power (via the ammeter) for the circuits not controlled by the ignition switch.

How can I use this wire to maintain supply to these circuits and get a true ammeter reading?

Thanks

[Andy Borris]

Should've added that the dynamo control box has long since disappeared, the wires were joined by neatly cut oblongs of copper!

[piman]

Hello Andy,

I'm not familiar with Bosch alternators, but unless there is an external regulator that won't be a field wire, ignition light is probable?
Without knowing how the modification is done it's difficult to know how your ammeter will read. If there is a connection that by passes it then it won't be accurate (Which is what it sounds like) but it will probably tell you if it is charging or not?

Alec

[Andy Borris]

Just in case anyone is interested in Bosch alternators.....the field wire and the ignition light feed are one and the same, the 2 wire Bosch alternator needs a resistor (30 amp I believe?) in the light circuit. If the ignition light blows, the alternator stops working without this resistor!

Can't use the ammeter on a MK1 with this alternator, it produces too many amps and may cause damage.

Andy