Lotus Elan and Lotus Elan Plus 2 Forums

miked wrote:Bill,
I have never seen the steering column dip switch carrying lamp load current. On any Plus 2 or S4 that I have worked on the column stalk operates the relay coils as you would expect. The volt drop would be significant if as you describe. Not being argumentative. Check a drawing.

Mike

Mike, it is as Bill described as on the S1 and S2 wiring diagram. There is only one relay which feeds power to the dip switch and then the headlights. Daft, I know.

As a matter of interest, my S2 which was modified around 1970 to include 26R style non pop-up lights was not provided with any relays at all and worked fine. When I put it back together I will put some in......

Interesting, thanks.
I have only been involved with later cars.

My S4 had 4 relays initially, Hbeams, Lbeams, horn, and the relay to flash the headlights. When I went to fuel injection I needed to add relays for the ECU, plus the ignition unit, fuel pump, and radiator fan as these are all operated by the ECU.

I decided to use the Bussman compact fuse/relay box combination illustrated. These are very compact, watertight, use standard metripack terminals, and are pretty cheap.

Since the Bussman boxes have 5 relays each and I needed six (I got rid of the flash circuit), I decided to use the remaining 4 relay sockets for the windows. I don't think window relays are necessary if everything is in order as the current draw was less than 4 amps on my car - less than the parking lights!

Tom

alan.barker wrote:Thanks Bill,
i've just learned something.
So it would be a good idea if i add 2 relays to my Sprint. 1 for main beam and 1 for dipped beam.
I could just unplug the bullets in each line near the Headlamps and insert the relays.
That way i don't need to change the wiring harness.
Alan

Alan, you should already have relays, ahead of the radiator on the LHS inner fender:

Thanks Phil,
that's what i said above. I've already changed one in the past.
But Bill seems to think Lotus did not wire them correctly
Alan

alan.barker wrote:Thanks Phil,
that's what i said above. I've already changed one in the past.
But Bill seems to think Lotus did not wire them correctly
Alan

It's not exactly incorrect, it's just not the best way to do it. The high current flowing through the dashboard lighting switch and the column dip switch will cause shortened life to those components.

billwill wrote:

alan.barker wrote:Thanks Phil,
that's what i said above. I've already changed one in the past.
But Bill seems to think Lotus did not wire them correctly
Alan

It's not exactly incorrect, it's just not the best way to do it. The high current flowing through the dashboard lighting switch and the column dip switch will cause shortened life to those components.

Bill, if we are talking S4, Sprint & probably later Plus2s the high power feed for the headlights comes straight from the Voltage regulator (blue wire) to the dipped beam & high beam relay, no fuse... The headlight & dip switches carry a small switching load; however when the flashing headlight function is used full current does go through the switch via the blue/yellow cable. However this should only be for a short period!

Please see this thread (http://www.lotuselan.net/forums/lotus-electrical-f38/late-federal-fail-safe-headlight-wiring-t30133.htmlwith my wiring diagram which is easier to understand than the one in the WSM.

And to get back to the original topic (!!); a relay should be used wherever high current is needed, regular electric horns & the electric radiator fan are examples where relays should have been used, but Lotus saved money by omitting them.

Phil,
We are not really talking about the S4s, but the earlier cars.

Since Lotus did it more sensibly in the later cars, thats all the more reason to rewire it that way in the earlier cars.

Could it be that Lotus had different people with different thoughts design the wiring for the models?
My 69 S4 has relays for dip and main with no fuses on the lighting circuit that I could see.. My 72 +2 has no relays on the lighting circuit with load going through the lighting switch then the thermal cutout then the dip switch to the lamps..

The Veg wrote:

Foxie wrote:The 12 fuse system in the Plus 2 is a great improvement on the original 2 fuse system used in the Elan.

Where are the other 10 located? I've only found 2 under the bonnet.

The original +2 only had the two fuses (one fuse box with two fuses), as per the Elans of the period, but the +2'S' had three fuse boxes each containing four fuses, mounted under the bonnet. They then went to one X Four fuse fuse box for the 'S'130's, mounted in the dash where the ash tray had been. Bit of a backward step IMHO, but I expect it save a few pence

Regards, Tim

So my Sprint has been wired correctly with relays
Many years ago i had a 1970 +2S which had lots of Fuse boxes and Relays all grouped together and i liked that
On my TVR 3000M i have added some Relays with built in Fuses which i think is a good idea.
Alan

I think the 4 fuse box is the best setup.

with the absence of the amp gauge and the fuses in the passenger compartment, the wiring harness is greatly simplified.

I am always confused with the profusion of fuses in modern cars, way more than required to protect wiring. Perhaps there is some other reasoning

Orsom Weels wrote:

The Veg wrote:

Foxie wrote:The 12 fuse system in the Plus 2 is a great improvement on the original 2 fuse system used in the Elan.

Where are the other 10 located? I've only found 2 under the bonnet.

The original +2 only had the two fuses (one fuse box with two fuses), as per the Elans of the period, but the +2'S' had three fuse boxes each containing four fuses, mounted under the bonnet.

Ah, well, that would explain it. My car isn't an S.

I'm following this topic with interest as I have an early +2 (2 Fuse). Although don't forget the in-line fuse that protects the radio !
on the subject of the [main] fuses... The only place I have found that lists the fuse rating is the parts manual. This suggests 35A or 5A... it's not clear whether this is one of each (and which circuit should have what) or a matter of choice / pot luck....
What should be fitted ? [Forgive me for politely overlooking the " a complete new fuse & relay box" replies].

Another option I am considering is a breaker type fuse, after the starter solenoid. I already have a 40A type - is this too low a rating ?

The car has a complete new loom and I've tried to ensure all the earths are good. an alternator is fitted.
I am replacing most bulbs with LEDs [except for indicators, charge warning light & headlamps; happy to review this if advised to the contrary].
Car does not have a heated rear window, nor extra front lamps

regards
Adrian

lucas 17 amp fuse, or US 20 amp are pretty close