Electrical Help

[gearbox]

Hi All;

Have been drilling down on a 1970 Plus 2 I just bought and trying to be as methodical as possible in trying to put back everything to original configuration as the PO had taken every electrical component off the car and pulled every wire from behind the dash and engine compartment. Most of the original harness is there but there are also lots of cut wires.

First of all, the car is registered as a 1970 Elan Plus 2 4 speed with a vin number of 50/1171 which I was told was an early 1969 build. The car is running a Lucas C40 generator and have a RB 340 control box. Again, all of the electrical components were removed and I found the control box loose from the car. On another thread, I was told that this car should have a two fuse Fuse Box which I didn't find, but bought a new one.

The first thing I did was to sort out the remote solenoid with a gear reduction starter I found in the trunk. Fashioned a jumper cable from the power cable to the starter solenoid so I can use the original remote solenoid. I have the battery power wire connected on one pole of the remote solenoid, along with two 10 ga. brown wires on the same pole. The opposite pole was connected directly to the starter. I found the white with red striker wire which I assume is the momentary power from the ignition switch, but the switch isn't hooked up so could not verify it just yet. But the push button works and cranks the motor. Further down the harness I have a white with yellow striker wire and solid white wire coming from the harness. I assume the WY is for the positive side of the coil and the solid white is for the oil pressure sender. This is where I'm getting lost. I found the heavy brown wire that is connected to the generator, but it comes out of the harness where the remote solenoid is and not on the other side of the car where I believe the RB 340 control box would be mounted to on the firewall. Also nearby next to the master cylinders, there are a couple of green wires coming from the harness which I assume connected to the fuse box. I see the brown with yellow striker wire going to the generator, but there is no BY (NY) wire exiting from the harness that should go to the control box. So a bit confused.

I have the factory manual which has 7 wiring diagrams of which 2 are with a generator. One is marked Elan +2 Non Federal, and the other Federal, but both diagrams show the system with 3 fuse boxes. Am I missing a page? And if so, does anyone have the single 2 fuse- fuse box wiring diagram for my car in high res so I can see the wire colors? Thanks Allan

[stugilmour]

Have tried to attach two scans of the diagram that might be what you need. Sorry if they appear upside down. May have to print them and tape together. Or perhaps someone with a 11 x 17 scanner at work can provide a better copy. Let me know if you need a better copy as I can maybe get my wife to scan from the book at work.

They are marked in the title block as

Lotus Elan Plus 2 Federal
RB 340 Control Box
March '68 to March '69

The dates are hand written, but were that way in my book copy.

My car is 50/2181 and originally followed this diagram pretty much exactly.

I notice this diagram calls up White / Black for the coil to dizzy wire, but I seem to recall my car had a different colour for that one. It is White / Yellow from the ignition switch to the tach and then to the coil after my re-wire in any case. The attached diagram calls up Red/Green for this wire, so really not sure on that one. Check if your anti-theft switch in the glove box is still in place.

White is usually reserved for Hot in Run and Start - Unfused. I think Oil Pressure is White / Brown. Has the tracer faded from the wire? I know I had a ton of issues with that on my car. I vaguely recall a rather heated discussion on this very wire colour confusion though.

The heavy gauge Brown at the solenoid runs to the ammeter. It changes colour at the ammeter to Brown / White according to the attached diagram.

The greens should be from one of the fuses, the one supplied by a Brown / White. The other fuse takes care of the purples, and is supplied by a Brown.

Sorry, the darned control box remains total magic to me, and I happily removed it when i rewired the car and installed an alternator.

Does your car have the flat rocker switches or the rat tail type?

The wire colours are all listed on the left side of the drawing and assigned call up numbers. Confusing at first buy OK once you are used to it. Note sometimes the same colour is listed twice in a different gauge (listed to the right).

HTH

Stu

[gus]

http://www.mgb-stuff.org.uk/colourcodes.htm

useful list

[gearbox]

Stu, Thank you, exactly what I am looking for, was this in the factory manual? As it is missing from mine, but the resolution is good enough to see the color codes. The harness that I have looks original, but not sure if the PO messed with it, so I may have to start cutting the wrapping off to trace the wires. But this is what I am dealing with and it is a mess lol. The fun just never stops, thanks again Allan PS do you have a picture of where the fuse box is located? I was told next to the masters, but only see one rivet coming through the horizontal body shelf, but it's on a crease, so not sure.

[stugilmour]

...was this in the factory manual? As it is missing from mine, but the resolution is good enough to see the color codes.

Allan, glad it helps. My manual is technically a reprint from the dude in Germany. I think they are hard bound Zerox copies of the original manuals.

http://www.lotus-books.com/elan.html

Lotus Elan +2 Workshop Manual. 500 pages, 2 heavy volumes, hardbound. Incl. the 5-Speed gearbox and all wiring diagrams. With additional restoration reports, buyers guide and history of the +2. Only available here from stock:
84,95 ?

I see in your picture you definitely have the flat dash switches. I just gotta believe you have an early Federal car that will largely follow this diagram.

Now that I am used to the diagram style I am OK with it, but it can be a b*tch to trace a wire through the layout. I had to often use the other schematic diagrams to understand a circuit, and then use this one to confirm how my car was wired, what colours, etc.

Best of luck. Heck, it's only a hobby!

Stu

[gearbox]

Reminds me of the paint by number kits from my youth lol. But the diagram is great, and the closest yet to what I have. But there are deviations. First of all, I do not know if the components I have is correct, and more importantly the harness. As mentioned, the PO had everything removed, the generator was just lying in the cradle, there was a gear reduction starter in the trunk, the RB 340 control box was found in a box, and I also found a Lucas alternator, so don't know if he was trying to convert over and how much did he do. I started to unwrap the harness to start tracing wires and the wires look brand new, and the wrap was nice and flexible, so it may have been re wrapped within the past decade. I found 3 holes in the firewall which aligned with the RB340 so placed that in position. So just drilling down step by step, albeit slowly.

This is the next challenge. I am tracing the generator wires, heavy brown and brown with yellow striker. The leads come out right by the generator from the harness, so these have to be the correct wires, plus they have the correct push on connectors. The other end of the heavy brown goes up along the harness and exits right by the solenoid along with the double brown wires which goes to the amp gauge (I think) and the ignition switch. The generator heavy brown wire had an original looking ring terminal which I replaced which fitted perfectly onto the solenoid pole. But when I had connected it, the generator started to spin like a electric motor lol. So that can't be right. From all my diagrams, it shows the the heavy brown wire going to the "D" terminal of the RB340 and the Brown with Yellow to the "F" terminal. But on my harness, the Brown Yellow disappears into the dash. On alternator cars, I see that a Brown/Black wire would go from the solenoid battery side directly to the alternator and the Brown yellow, to the Tach.

Despite having a solid brown heavy wire instead of the Brown Black the alternator diagram shows, it may have a alternator harness. Maybe. So either the PO changed the harness or this car was originally an alternator car? My vin is 50/1171, should it be an alternator or a generator? I'm sure I can alter the harness for the generator, but would like to keep it somewhat original to how the car was made. Any ideas before I start to cut up the harness? Any problems can anyone foresee down the road in converting this harness to a generator given that it may be originally an alternator harness? Should I be building this with the alternator? Did this car originally come with an alternator? So many questions and so little time lol. But the fun just never stops. Let me know what you guys think, thanks Allan

The generator Heavy Brown and Brown Yellow exits the harness where it should

At the firewall "Y" split, the heavy Brown makes a left turn and the Brown Yellow disappears into the dash.

The Heavy Brown wire exits the harness right by the solenoid.

[KevJ+2]

Before I started chopping up my loom, I made a list of colours and locations. My car (RHD) is not far off your number (Generator was fitted) so it should be pretty much the same.
It might help

ELAN Plus 2 Wiring Colour List.pdf

(194.99 KiB) Downloaded 467 times

[gearbox]

Thanks Kev, between your list and Stu's diagram, I have a starting point. But I am begining I think I have the wrong harness in this car, close and most likely for an alternator, but I think I can make it work. Thanks again Allan PS, can you tell me were your fuse box and relays are located? I believe the fuse box should be near the masters on a LHD car and the relays on the left side of the radiator. I only see one relay for the horn (red) and nothing else. Also what relays do I need?

[stugilmour]

Great connection list Kev. That's a keeper for sure. Thanks for posting.

Allan, agree it really does look like a replacement loom from your pictures. The wire colours are certainly way brighter than my car had originally, and it looks like it could be more modern thin wall wire. That would certainly explain some of the wire colour discrepancies like the ignition wire as White / Yellow (similar to the British Standard BS-AU7 that Gus posted) rather than Red / Green. Just knowing you will have some differences is a big help.

When you get to checking out the side light and headlight circuits maybe post a new topic in electrical if it doesn't come together easily for you. There are several versions of these circuits in the various Plus 2 models, and heaven knows if the replacement loom is 'correct' to your versions and locations of the microswitches, dash switches, and relays.

Assuming it is a loom set up for an alternator, I personally would buy a Nisson Denso unit with the correct mounting hardware from Dave Bean or Ray at RD and leave the control box out of the car. It is just so much simpler and more reliable. Your car, your choice though.

The Brown / Yellow is indeed for the ignition light located in the tach. The other side of the light comes from the ignition switch. Apologies if you know this already, but the light filament has to be working to provide excitation current to the alternator coils. Once the alternator is making juice correctly the Brown / Yellow goes to the same voltage as the ignition switch and the light goes out (12 volts both sides of the bulb). I assume it works in a similar fashion with a generator setup, but not sure of the details with the control box.

I tried to find good photo's of my original fuse box location, but they were way too blurry to be of use. Flat area by the pedal box sounds right; I think I had earlier suggested the fire wall by the control box which was incorrect.

According to Robinshaw & Ross the Plus 2 only went negative ground for all markets at 50/1087 and revised control box at 50/1589. I assume the alternators were much later; my car was originally Dynamo.

Stu

[gearbox]

Hey Stu;

It's certainly beginning to look like a replacement harness. Good and bad I guess. But on your alternator set up, the RB340 control box is deleted and no other control box is required yes? And is the heavy brown wire from the alternator now connected directly to the + side of the battery via the solenoid? I did find a 18ACR Lucas alternator in the trunk, so possible the PO was in the middle of a conversion. A shame though after rebuilding the C40 generator it looks so pretty sitting in place lol. But I had installed one of those Nippon Densos on my Elan rebuild. Didn't wire it up yet as I am still working on the body, but those things are tiny. Not opposed to converting to an alternator and possibly the 18ARC or a Nippon Denso would be the path of least resistance (a little electrical humor there). But let me know about the two questions above and I'll commit one way or another. Thanks Allan

[stugilmour]

Yes, no control box required with the modern alternators as it is all internal.

I did run a ground wire to the alternator case. The small brown / yellow goes directly to the alternator from the ignition light.

I believe the large Brown that comes from the alternator goes through the ammeter and then to the solenoid terminal. The large black cable takes the charging current from the solenoid terminal on to the battery positive terminal.

The rest of the loom attaches on the alternator side of the ammeter, presumably at the control box location, either with a stripped down version of the control box or a bus of some sort. The ammeter deflects positive if current is flowing from the alternator to the battery, and negative if flowing from the battery to the loom (i.e. the alternator can't keep up with the loom loads).

I deleted the ammeter and replaced with a voltmeter (or Battery Condition Gauge in Lotus parlance). This makes my modified wiring a bit easier physically, as the brown from the alternator and the loom take-off can all be positioned at the solenoid position. I placed all the fuses and relays on the back wall of the glove box where they stay clean and dry.

Stu

[The Veg]

Allan, I have 50/2036 (federal car) and it was originally equipped with a generator* so I'd be confident to infer that yours was too. Also I concur with Stu; the alternator is the way to go.

*A previous owner installed an alternator and the generator is now in the very heavy box of obsolete original parts that came with the car (Rotoflex driveshafts, etc.).

[gearbox]

OK, you guys convinced me, the alternator it is. I think I'll rebuild the Lucas 18ACR for now and see how it works. Now all I have to do is to figure out the hybrid wiring for the alternator and 2 fuse Fuse box. I was going by this diagram to wire the Elan when I got around to it so I think the amp meter should be between the ignition switch and the solenoid? Thanks Allan

[stugilmour]

Allan, this diagram from the site shows the ammeter wiring a bit more clearly.

http://www.lotuselan.net/wiki/Classical ... ng_Diagram

In effect the ammeter is between the large gauge alternator output lug and the battery. In the Smiths diagram imagine all the loom loads being attached at the dot immediately above the ammeter. Physical location for this point in your car is in effect by the control box area, where a main runs to the fuse box and another main runs to the ignition switch. Depending on some of your loom details, there may also be some unfused loads attached as well, notably the headlamps. The ammeter is located 'downstream' of this point, and 'upstream' of the solenoid lug where the main positive battery cable is attached. It uses heavy gauge wiring as it sees all the charging current to the battery or all of the battery current to the loom loads when the alternator is not charging. Under normal running conditions the ammeter sees the alternator output less the current that is supplying the loom loads.

Also note the big cable to the starter motor (which is of course physically located at the solenoid on the other side of the solenoid switch) would be attached immediately below the ammeter in the Smiths diagram; i.e. It receives current directly from the battery and the high starter motor current does not go through the ammeter.

The other issue to check / consider is your alternator output. It may exceed the scale on the stock ammeter, that was presumably sized for the low output of the generator. The use of a voltmeter gets around this limitation, as it only requires small gauge wire connected as shown in the Smiths diagram. There is a write up in the Plus 2 Workshop Manual describing changing to a voltmeter when retrofitting an alternator. Your call if you see this as an issue or not.

I am not familiar with Lucas alternators to know if that particular model has the internal regulator. I understand there were Lucas alternators that used an external control box, but I am not familiar with the details. Just tossing that out as something to check.

HTH

Stu

[rgh0]

The very early Lucas alternators were numbered 15AC and 17AC and had an external control box. They later changed to the 15 ACR and 17ACR etc which had the internal control. I presume the AC stands for "alternating current" or similar- i.e. alternator not generator and R when it was added stood for "Regulator" for it having the internal regulator

I remember replacing the generator on my Hillman Imp in the about 1970 with a 15AC alternator with external control box

cheers
Rohan