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new early Plus 2 loom surprise

PostPosted: Sat Aug 03, 2019 6:29 am
by bill griffiths
elanmainfeed.jpg and
I purchased a new loom from one of the usual UK suppliers and installed it in the course of a total (my third in the last 45 years) rebuild.
But I am baffled!
Am I missing something?
I shall attempt to attach a photo of the mail feed from the solenoid. Brown with blue; in this case brown with a sleeve of blue heatshrink. Quite satisfactory, and not confused with the thick plain Brown running to the same place from the alternator. (I ordererd a modified loom for an alternator.)
The Brown with blue sleeve runs forward, does a short tour of the nose with its friends and returns, in the loom, past a few relays and then through the firewall to cascade above the passenger's lap.
Ready to be connected to the dash loom.
Here's the mystery. There is no electrical connection between the Brown/blue in the picture and the wire of identical appearance above the passenger's lap!
Since I am installing a battery switch above the handbrake and a couple of fusible links (the new ones are very neat!) for the main feed and the alternator it presents no great problem; remember the early Plus 2s ... and the best...have a grand total of TWO fuses only... Unless I am missing something basic!
I cut into the wire to check for a dry connection but I remain baffled but for a faulty loom.

Re: new early Plus 2 loom surprise

PostPosted: Sat Aug 03, 2019 4:14 pm
by wotsisname
Bill, not entirely sure this helps...
Brown with a blue stripe is Lucas for control box (dynamo) to switches.

My early +2 loom is pretty much as oe with some mods I have slowly added. There's a pair of beefy cables just behind the dash that attach to the ammeter.brown. And brown/white. The other end of the brown one is at the solenoid. Brown/ white at the control box.
The solenoid also has white/red from ignition.
The usual mod for alternator is to run a thick cable direct from alternator to battery using the solenoid as a convenient live connection to the battery. Then cut and join a bunch of wires at the control box. I'm choosing to use the control box with the insides ripped out as a junction box.


Re: new early Plus 2 loom surprise

PostPosted: Sun Aug 04, 2019 10:33 am
by Higs

You are basically correct. The brown/blue, with an alternator, goes directly to the brown/blue behind the dash. You just seem to be missing the connectors!

Adrian is correct in the conversion to alternator - but you do end up connecting a brown/white to a brown/blue which is a bit odd. With a new loom you can be consistent with the colours. The reason the blue shrink wrap is there is that you cannot buy a brown/blue wire of sufficient size to take the current.


Re: new early Plus 2 loom surprise

PostPosted: Mon Aug 05, 2019 4:22 pm
by gus
There is bound to be some weirdness in an early +2 with alternator, as most alternator cars would not have a ammeter.
From the S diagram, I think it is an alternator battery sense wire. Should go to the solenoid on an originally alternator equipped car with a volt gauge

I have 8 wiring diagrams in my +2 manual.

The 'S' diagrams show a brown/black NB, wire going from the alternator to the positive take off of the solenoid, electrically same point as the battery, and the same point that the brown/white NW alternator output wire goes. Battery sense I think.

The 'S130' diagrams delete this wire

The others are all labeled by their control box number, meaning generator no alternator.

generator diagrams have no brown/blue or brown black that I can see. Brown goes from amp gauge to solenoid[battery] Brown white from amp gauge to control box, and I think from there to power the fuse box etc.

I am thinking that the brown blue you have is meant to go to the amp gauge and really ought to be brown white to feed the fuse box, but again this is where the two style harnesses have to be reconciled.

Re: new early Plus 2 loom surprise

PostPosted: Mon Aug 05, 2019 4:36 pm
by gus
There is a brown/blue that goes from the control box to the ignition switch and also turns into pink and feeds other things....

I have run for decades with no alternator sense wire.

I think I would ignore it or call it brown white and feed the fuseboxes from it

Re: new early Plus 2 loom surprise

PostPosted: Tue Aug 06, 2019 4:33 am
by bill griffiths
Thanks to all for your help.
The manufacturer says sorry. The fact that the two ends of the relevant feed are without resistance indicates a fault in the loom. Now that I know, it is of no consequence. I am installing a battery switch near the rear of the firewall on the off side and running the alternator directly to the ammeter via a fuse in case it gets carried away! Regards, Bill.