headlight wiring

[seniorchristo]

I am wiring a Plus 2 using bits from cars of various years. Thumbing through the multiple wiring diagrams, I see various configurations of headlight wiring. Some with relays and some without. I want to eliminate the headlight flashing feature using micro switches and only flash while headlights are on and up. I can do this using the column switch.
Early Plus 2's use a relay which then sends the current through the column switch and on to the headlights. Wouldn't it make more sense to move the relay after the switch and closer to the headlights. Also, the wiring in the flasher switch seems quite small to handle the headlight current. I thought the signal wire running to a relay was small while the wire running to the load was generally heavier gauge.
Thanks
Chris

[HCA]

The only purpose of a relay is to assist with any part of a circuit that cannot cope with the current required to operate the load - usually the contacts of modern switches. It does not matter exactly where the relay is placed providing the cable sizes are correct on the primary and secondary circuits.

I cannot suggest how exactly to plan yours, other than agree, yes the column flasher switch wiring should not take the full load and therefore be the ptimary side of a relay.

I never fathomed why the Elans went in for all the weight and complexity of retracting lights. Someone at least wised up to it with the 26R!

I have alwas thought the +2 would look equally as pretty eith a Europa front.,,

[JonB]

I never fathomed why the Elans went in for all the weight and complexity of retracting lights.

Fashion and looks, I imagine. Pop up headlights were all the rage back then. Some aerodynamic benefits when retracted, perhaps?

[Elanman99]

The main reason for the pop up headlamps was to comply with vehicle 'construction and use' regulations that stipulated the min and max height above the road surface. Not sure but 24" (to the centre of the lamp) comes in my mind,

26R was for the track only.

Ian

[HCA]

Yes! I remember now!

Typical: regulations get in the way of everything!

[gus]

The wiring on my 2 fuse functions IIRC:
Dash pull switch provides ground to both relay coils
Relay contacts have power at all times
column stalk sends 12 volts to one or the other relay coils
Relays are located at front corner of engine bay resulting on a fairly short high current path.

[gus]

Glancing at a 3 fusebox diagram on this site and it appears they work the same, with fuses on the output side for the bulbs

[seniorchristo]

Will this diagram work? Also, does the fuses in the relays shown protect only the load circuit? Should a fuse be added to the signal circuit? Thanks



https://www.amazon.com/Nilight-Waterpro ... atf_m&th=1

[gus]

How do you turn the headlights off?
HOw do you power the valve/motor for the headlights?
high beam light?

These issues are solved by instead of grounding the relays, use the headlight switch to ground them, so that no matter which relay is active, the valve or motor remains enabled

Believe it or not the factory wiring is logical, it is just frequently undersized or has poor connectors
I completely rewired my car almost 30 years ago and used almost all the factory logic in doing so

[gus]

I see, you don't show the switch logic, so that is a switch for the headlights

[gus]

[img][img][/img][/img]

crude representation of early plus two headlight wiring

pins on relays not intended to be representative

Mistake I made in rewiring?
grounded the hi beam light to ground, rather than to the switch. Had to put a diode in the high beam enable at the relay or the headlights came on all the time. high beam light comes on when the stalk is in that position even if headlights are not on, but who cares.
It is a pretty simple setup that works.
They were unfused on the two fuse cars
If you are adding fuses, a common fuse for both lights[two fuses total] is enough to protect the wires, although Lotus apparently added 4

[corrected shematic added 12 volt to relay]

[gus]

Looks like the late 4 fuse used a thermal cut out rather than a fuse. Makes sense since with fuses on the dash you would need to run big wires back and forth with relays and fuses. I don't like the lack of relays
I have never missed the lack of flash from the stalk, and I don't think most have that as the wiring gets silly I think

[JonB]

When I did mine, I used the existing wires to energise the relays, and fitted relays with built in fuses. Then I laid a nice fat cable from the starter relay to a bus bar, and another from the chassis bolt to another bus bar. Simple matter then of running new wires to the lights from the bus bars via the relays. I also added relays for the horn and radiator fan, wired in the same way.

Then I wrote it up here: viewtopic.php?t=40758

I left the thermal fuses in place…

Later on I decided to tidy it all up: viewtopic.php?t=45352

Cheers
JonB

[gus]

You know that is a good idea, I used one of those relays in my Exige and that would be a great solution for the underfused state of the early and late headlights

[seniorchristo]

Gus

My diagram is almost identical to the factory Elan +2 schematic except I am eliminating the flash feature and using (2) relays after the column switch instead of before as Lotus does. The light switch is the two position toggle switch wired exactly as per Lotus. I am raising the pods via a Spyder conversion which raises them anytime the sidelights are energized.

Do the fuse/relays discussed protect only the load circuit? Should a fuse be added to protect the signal circuit? thanks Chris