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Lucas fuse box - Picture

PostPosted: Fri Mar 25, 2016 4:31 pm
by Jimnic007
Afternoon all,

Me again, does anyone have a picture of their Lucas fuse box on the bulkhead of their Elan Sprint? I have a 1972 Sprint in the UK and I have a loose spade connector which is green and white and I am not sure where it connects.

Since connecting this in the location I thought it should go, the engine will not turn off, even with the key removed. However my indicators are working again!!!

Don't you love Lotus wiring and electrics.....

Cheers,
James

Re: Lucas fuse box - Picture

PostPosted: Sat Mar 26, 2016 12:37 pm
by pharriso
This wiring diagram should be helpful

S4 electrical diagram color coded.pdf
(78.3 KiB) Downloaded 473 times

Re: Lucas fuse box - Picture

PostPosted: Sat Mar 26, 2016 3:10 pm
by stugilmour
James, looking at both your posts it does appear you have some crossed wires in the indicator circuits and/or hazard circuits.

First confirming the wire you are unsure of is a single Green / White wire (not a Green wire and a separate White wire)? The Green / White is supposed to be from the flasher unit to the right side indicator bulbs. It should only be intermittently hot with the key in he run position and the turn signal column stalk in the right turn position or the hazard switch in the on position independent of the key position. It definitely does not connect to the fuse box, if that is what you tried?

The 'green' fuse is supplied by White, hot in run and start, Unfused from the ignition switch. As noted in the excellent diagram, this fuse output supplies all of the accessories that are only hot when the key is on, including the turn signals. The Green wires (Hot in run and start, Fused) supply all of these circuits as listed on the diagram.

As mentioned in the other thread, it seems the Green and Green / White wires may be crossed up at the flasher unit(s). I think that is a good place to start. I say flasher units as there are two; one for the indicators and one for the hazards. According to the diagram the hazards are supplied by Brown, Hot at All Times, Unfused, whereas the indicators are supplied by the Green, Hot in Run and Start, Fused. Getting this wiring crossed up (by misconceived wires, a failed switch, jammed flasher, etc) could be back feeding your ignition circuit and keeping the car running independent of the key position.

To help decipher the flasher terminals, I believe P is 'Pilot' connected to the dash indicator lamp, B is 'Battery' or flasher power supply, and 'L' is Lamp or flasher output.

Assuming you have confirmed the ground integrity at all four lamp housings?

HTH

Stu

Re: Lucas fuse box - Picture

PostPosted: Sat Mar 26, 2016 8:39 pm
by Jimnic007
Stu,
Thanks very much for your very considered post. Thanks also for the wiring diagram Phariso.

I took the green/white wire off the fuse box and the indicators are still working, great. I will check the hazards tomorrow to see if they are working. If the ignition is also working again we are in good shape. Just need to work out where the green/white female spade connector needs to fit in the engine compartment.

I will study the wiring diagram in more detail, but the lose green/white wire (with a female spade) comes out of the loom which comes through the bulkhead from the dash. There is only a short amount of green/white wire exposed from the loom and this would only be long enough to connect onto the fuse box in theory as it is in very close proximity to the box.

Could it be that it is not meant to connect to anything, even though it has a spade connector on the end of it?

The plot thickens, but I do agree, that is the cleanest version of the wiring diagram that I have seen yet.

Thanks again all, happy Easter!!
James

Re: Lucas fuse box - Picture

PostPosted: Sat Mar 26, 2016 9:42 pm
by gjz30075
My Federal 72 Sprint. Solid green goes back into the car and the smaller green comes from the backup
light switch (on the g'box)

Re: Lucas fuse box - Picture

PostPosted: Sun Mar 27, 2016 5:01 pm
by Jimnic007
Here are a few pictures of my fuse box, the green/white wire is a single wire and doesn't currently have a home. Any idea where it should connect?

Thanks

Re: Lucas fuse box - Picture

PostPosted: Sun Mar 27, 2016 6:18 pm
by billwill
You will get nowhere until you fiind the other end of that wire and see what it is supposed to do.
When you think you found it, use a continuity meter (ohmmeter) to check that it really is the same wire.

Get clues as to where the other end might be by studying the wiring diagrams available on this site looking for green/white wire colours.

It may well be just a spare wire for an optional device/service that you don't have on your car.

Green/White on the original Elan wiring diagram was designated for the Right-Side flasher lights and only went from the flasher switch to those lights, so I can't see why it was near the fuse box.

Re: Lucas fuse box - Picture

PostPosted: Sun Mar 27, 2016 6:28 pm
by billwill
A list of normal UK car wiring colours can be found here: http://www.autoelectricsupplies.co.uk/p ... ng_colours
and here: http://www.speedycables.com/greengauges ... lours.html


And indeed Green/White is for right hand indicators, but White/Green is for fuel pump or for Wiper motors.

Could it actually be Green and faded Yellow? That would officially be Heater Control.