I've been trying to get my car going this week and am getting nowhere fast... The problem is that when I switch on the ignition everything stays dead and nothing happens. I originally had a Metro ignition switch fitted which has the brown wire in the centre and the three others round about it. I changed that for an Allegro one which has 4 wires round the edge and plugs directly in with the wires matching the loom exactly but it's made no difference. The car has a brand new wiring loom fitted (from Rossabitz) but I'm wondering about the compatibility of the starter solenoid etc.

The solenoid has a pole terminal which takes the live direct from the battery and also a ring connector with two brown wires of different thicknesses which go direct to the alternator plug. There is a large male spade connector which takes another brown wire and, finally, a smaller spade right underneath the solenoid to which I have put a white/red wire.

When I turn the key there is no power coming forward to the dash. If I take a feed direct from the battery to the brown terminal on the ignition switch the engine turns over (regardless of where the key is) and the large brown wire to the spade on the solenoid becomes live. If I put that feed on the white/red wire on the switch nothing happens unless I move the key to the 'start' position and then the engine turns over as above. I thought that the brown wire on the switch should always be live but from the above it looks as if it should be the white/red one. Which one is the correct one and where does it take its power from? I got a wiring diagram from Alan with the loom and it shows a brown going from the solenoid to the switch and another going to the alternator whereas I have two browns connected together going from the solenoid to the alternator.Confused? you bet I am

Have you checked your fuses? - Have you a multi meter?

You need to check that you have power to the ignition switch, then check to see if the switch is working.

I've found the following usefull:

What The Colours Mean:
BROWN is for direct, unswitched, unfused supply from the battery. Seen on wires to alternators, dynamos, control boxes and ignition switches etc. Always live and often carrying heavy current.

YELLOW sometimes used as an alternative to brown on older cars. Also used on solenoids and overdrive switches.

PURPLE Direct, unswitched but fused supply from the battery. On older cars with no purple wires, brown wires with a secondary tracer colour are used.

WHITE Unfused supply from the ignition switch.

GREEN Fused supply switched via the ignition switch. Used for things like the wiper motor, indicators and brake lights which only work when the ignition is on.

BLUE The main colour for front lights- headlamps and spotlamps.

RED The main colour for rear and side lights.

BLACK Usual colour for wires from components to earth points on the body.

These refer to the main colour of the wire. The second tracer colour which is on many wires is the thinner line and is used to identify the wire. There is a certain amount of logic to them too as you will see.



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Below is the colour code table for BS-AU7a which was amended in the 'eighties so there will be a few variations on our '50s to '70s cars..

Main colour is given first , tracer second

MAINLY BLACK WIRES
Black All earth connections
Black/ Brown Tachometer generator to tachometer
Black/ Blue Tachometer generator to tachometer
Black/ Red Electric or electronic speedometer to sensor
Black/ Purple Temperature switch to warning light
Black/ Green Relay to radiator fan motor
Black/ Light Green Vacuum brake switch or brake differential pressure valve to warning light and/or buzzer
Black/ White Brake fluid level warning light to switch and handbrake switch, or radio to speakers
Black/ Yellow Electric speedometer
Black/ Orange Radiator fan motor to thermal switch


MAINLY BLUE WIRES
Blue Lighting switch (head) to dip switch
Blue/ Brown Headlamp relay to headlamp fuse
Blue/ Red Dip switch to headlamp dip beam fuse. Fuse to right-hand dip headlamp
Blue/ Light green Headlamp wiper motor to headlamp wash pump motor
Blue/ White a) Dip switch to headlamp main beam fuse
b) Headlamp flasher to main beam fuse
c) Dip switch main beam warning light
d) Dip switch to long-range driving light switch
Blue/ Yellow Long-range driving light switch to lamp
Blue/ Black Fuse to right-hand main headlamp
Blue/ Pink Fuse to left-hand dip headlamp
Blue/ Slate Headlamp main beam fuse to left-hand headlamp or inboard headlamps when independently fused
Blue/ Orange Fuse to right-hand dip headlamp


MAINLY BROWN WIRES
Brown Main battery lead
Brown/ Blue Control box (compensated voltage control only) to ignition switch and lighting switch (feed)
Brown/ Red Compression ignition starting aid to switch. Main battery feed to double pole ignition switch
Brown/ Purple Alternator regulator feed
Brown/ Green Dynamo 'F' to control box 'F' Alternator field 'F' to control box 'F'
Brown/ White Ammeter to control box. Ammeter to main alternator terminal
Brown/ Yellow Alternator to 'no charge' warning light
Brown/ Black Alternator battery sensing lead
Brown/ Slate Starter relay contact to starter solenoid
Brown/ Orange Fuel shut-off (diesel stop)


MAINLY GREEN WIRES
Green Accessories fused via ignition switch
Green/Brown Switch to reverse lamp
Green/ Blue Water temperature gauge to temperature unit
Green/ Red Direction indicator switch to left-hand flasher lamps

Green/ Purple Stop lamp switch to stop lamps, or stop lamp switch to lamp failure unit

Green/ Light green Hazard flasher unit to hazard pilot lamp or lamp failure unit to stop lamp bulbs
Green/ White Direction indicator switch to right hand flasher lamps
Green/ Yellow Heater motor to switch single speed (or to 'slow' on two- or three-speed motor)
Green/ Black Fuel gauge to fuel tank unit or changeover switch or voltage stabilizer to tank units
Green/ Pink Fuse to flasher unit
Green/ Slate a) Heater motor to switch ('fast' on two- or three-speed motor)
b) Coolant level unit to warning light
Green/ Orange Low fuel level switch to warning light
Light green Instrument voltage stabilizer to instruments
Light green/ Brown Flasher switch to flasher unit
Light green/ Blue a) Flasher switch to left-hand flasher warning light
b) Coolant level sensor to control unit
c) Test switch to coolant level control unit

Light green/ Red Fuel tank changeover switch to right-hand tank unit or
entry and exit door closed switch to door actuator
Light green/ Purple Flasher unit to flasher warning light

Light green/ Green Start inhibitor relay to change speed switch; or switch
to heater blower motor second speed on three-speed unit
Light green/ White Low air pressure switch to buzzer and warning light
Flasher switch to right-hand warning light; or
Light green/ Yellow differential lock switch to differential lock warning light
Light green /Black Front screen jet switch to screen jet motor

Light green /Slate Fuel tank changeover switch to left-hand tank unit; or entry and exit door open switch to door actuator

Light green/ Orange Rear window wash switch to wash pump; or cab lock-down switch to warning light


MAINLY ORANGE WIRES
Orange Wiper circuits fused via ignition switch
Orange/ Blue Switch to front screen wiper motor first speed timer or intermittent unit
Orange/ Green Switch to front screen wiper motor second speed
Orange/ Black Switch to front screen wiper motor parking circuit, timer or intermittent unit
Orange/ Purple Timer or intermittent unit to motor parking circuit
Orange/ White Timer or intermittent unit to motor parking circuit
Orange/ Yellow Switch to headlamp or rear window wiper motor feed, timer or relay coil
Orange/Light green Switch to headlamp or rear window wiper motor parking circuit timer or relay coil
Orange/ Pink Timer or relay to headlamp or rear window wiper motor feed
Orange/ Slate Timer or relay to headlamp or rear window wiper motor parking circuit


MAINLY PURPLE WIRES
Purple Accessories fed direct from battery via fuse
Purple/ Brown Horn fuse to horn relay when horn is fused separately
Purple/ Blue Fuse to heated rear window relay or switch and warning light
Purple/ Red Switches to map light, under bonnet light, glove box light and boot lamp when fed direct from battery fuse
Purple/ Green Fuse to hazard flasher
Purple/ Light green Fuse to relay for screen demist
Purple/ White Interior lights to switch (subsidiary circuit door safety lights to switch)
Purple/ Yellow Horn to horn relay
Purple/ Black Horn to horn relay to horn push
Purple/ Pink Rear heated window to switch or relay
Purple/ Slate Aerial lift motor to switch up
Purple/ Orange Aerial lift motor to switch down


MAINLY RED WIRES
Red Main feed to all circuits mastered by sidelamp switch
Red/ Brown Rear fog guard switch to lamps
Red/ Blue Front fog lamp fuse to fog lamp switch
Red/ Purple Switches to map light, under bonnet light, glove box light and boot lamp when sidelamp circuit fed
Red/ Green Bulb failure unit to right-hand-side and rear lamps
Red/ White a) Sidelamp fuse to right-hand side and rear lamps
b) Sidelamp fuse to panel light rheostat
c) Fuse to panel light switch or rheostat
d) Fuse to fibre optic source
Red / Yellow Fog lamp switch to fog lamp or front fog fuse to fog lamps
Red/ Black Left-hand, sidelamp fuse to side and tail lamps and number plate illumination
Red/ Pink Sidelamp fuse to lighting relay
Red/ Slate Lamp failure unit to left-hand side and tail lamps
Red/ Orange Fusebox to rear fog guard switch
Red/ Slate Window lift main lead


MAINLY WHITE WIRES
White Ignition switch or starter solenoid to ballast resistor

White/ Brown Oil pressure switch to warning light or gauge, or starter relay to oil pressure switch. Choke switch to choke solenoid (unfused) and/or choke to
White/ Blue switch to warning light, or electronic ignition distributor to drive resistor. Starter switch to starter solenoid or inhibitor switch
White/ Red or starter relay or ignition (start position) to bulb failure unit
White/ Purple Fuel pump no 1 or right-hand to changeover switch
White/ Green Fuel pump no 2 or left-hand to changeover switch. Start switch to starter interlock or oil pressure switch
White/ Light green to fuel pump or start inhibitor switch to starter relay or solenoid
White/ Yellow Ballast resistor to coil or starter solenoid to coil. Ignition coil contact breaker to distributor contact
White/ Black breaker, or distributor side of coil to voltage impulse tachometer
White/ Pink Ignition switch to radio fuse
White/ Slate Current tachometer to ignition coil
White/ Orange Hazard warning lead to switch
White/Yellow (or just plain yellow) a) Overdrive b) Petrol injection c) Door locks d) Gear selector switch to start

YELLOW WIRES
Yellow (or yellow/white) a) Overdrive b) Petrol injection c) Door locks d) Gear selector switch to start

PINK WIRE(!)
Pink/ white Ballast terminal to ignition distributor

Thanks for all that Allen - I hope you cut and pasted it rather than typed it!!! I'v printed it off for future reference - it's very useful to have. Ta.

The fuses are fine and I've been all over it with a multi meter, test lamp, hammer etc....
There is no power at the ignition switch and I can't see where it should come from - this is the part I'm having most difficulty understanding.Everything is wired up as per the book apart from one bit (see below re brown wires) and there are no spare wires or connections anywhere. The connections to the solenoid can only be made one way because of the different types of connector. However, I noticed today that the terminal from the battery which also has another terminal on it which has two brown wires joined together both going (as far as I can tell without stripping the loom) to the alternator plug and this slightly different from the wiring diagram. As the loom is brand new I hav to take it as being correct (for the moment) and I'm reluctant to start altering it..... I think I'm going to need to get an auto electrician to take a look at it next. As a matter of interest, if I put a live straight from the battery to any brown wire at all the engine turns over so they're obviously all connected somewhere and that's what makes it impossible to check where the two that are joined together at the solenoid go to.

Yes, cut and pasted and invaluable when I re-wired the dashboard (custom dash and Acewell didgital dash)

Is there power to the multi connector joining the loom to the ignition switch? Sometimes they don't always conenct properly when seemingly pushed home OK.

What else is live in the system?

It is quite common to have two brown wires on the alternator - sometimes they join into one thicker one in the loom.

I assume the main battery cable goes from the battery to the starter solenoid, and a feed goes from there back to the c\bin to feed everything else?

Regards,

Allen

There is power at the solenoid from the battery direct lead and that's it. It doesn't go anywhere else and I have checked the multi pin connector at the ignition switch with a meter None of the other terminals on the solenoid are live until I take a direct feed from the battery to a brown wire when the braided wire from the solenoid to the starter goes live as does the brown wire on the big spade which is the one I expect to take current back into the car. The same result happens when I take the direct feed to the white/red wire on the ignition switch. It's this inability to get power to the switch that I don't understand. If, as I suspect, the brown wire from the big spade takes power back in to the car what is there to interrupt the starter circuit once the engine runs (hopefully!) because I presume that it will also power the starter switch (turning the starter motor once the key is moved round to the white/red wire) yet a direct feed to that brown powers the starter and keeps on doing so until I take the wire away - it seems to be shorting back into the switch somehow I don't know f you can understand what I'm trying to say but it's a bit complicated to explain

Not sure if I entirely understand. Brown wire/wires go to solenoid, main battery cable goes from solenoid to battery +, i.e. they meet/join on the switchable side of the solenoid, a feed to the solenoid (from the ignition switch, which is live with the switch in the start position) makes the contacts close and connects the main battery cable thru to power the starter, another wire from the ignition powers the coil and provides the spark (live with ingition in on position). You are saying there is no power coming through the loom to be switched by the ignition switch.

Sounds like the brown wire to the ign switch is not connected to anything - I assume it would either be an extra lead on the battery+ or joins the brown from the alternator and the + battery cable on the solenoid.

Could you have any of the wires on the wrong terminals on the solenoid?

Allen

Hi Allen. I have a live from the battery to the solenoid and on the same terminal there are also two brown wires on a common ring connector which go to the alternator. Beside them there is a large spade connector that also takes a brown wire and I suspect that this is the one that's meant to take power into the car. On the other side there is a braided wire that goes into the starter motor and, finally, underneath there is a spade that takes the white/red from the ignition switch. It's clear where everything goes but I've had a go at moving them around with no success other than to create a lot of sparks when the live touched the other side and the engine turned over unexpectedly However, I've just been looking at starter motors on ebay and I found an Allegro/Metro one that has a pic of the end of the solenoid http://cgi.ebay.co.uk/AUSTINALLEGRO-MET ... 58841dc5f8 You can see that the large spade is connected directly to the terminal but mine is not like that. It is not joined at all like in the link but has what looks like a wire coming from behind it and is soldered to it so I took it that the connection is internal but maybe it's not. Tomorrow I'll try putting the wire that's meant to go on the spade on to the battery live and see what happens. I'll let you know how I get on.....

Do the lights/wipers etc working? Thinking about it, the brown wire should be the main feed for all power at the dash and should go to the fuse box and supply the fused supplies etc.

Allen

Nothing else is working. Power gets as far as the solenoid and then stops. Today I tried putting the brown cable from the large spade together with the battery live and the whole dash came alive! I had ignition and low oil pressure lights and all the brown wires around the dash area had power. That is the good news........the bad news is that despite the white/red from the switch now having power the starter still doesn't work I don't know whether this is due to the large spade on the solenoid now having no lead on it or whether the solenoid is discumknackerated. It may even be that the solenoid is fine but is incompatible with the wiring in some way. Boogah! Back to the drawing board,I suppose

I also had the starter motor off and took a photo of the end of the soleoid so that you can see how it differs from the one for sale on ebay in the link above. The large spade is not integral with the screwed terminal and it does have a wire coming out of the solenoid soldered on to it



Raymond (now getting thoroughly pi$$ed off )

Sounds like progress to me.

The lefthand terminal marked 15A(?) takes the starting wire from the ign switch.


If you apply 12v+ to the spade terminal (and earth the body), you should get continuity between the
two other terminals i.e. the starter should operate if connected properly. Testable with jump leads - put foot firmly on starter cos it kicks quite a bit.

Regards,

Allen

Ah! Smashing! Something to do tomorrow then Thanks.

Regards,

Raymond

Hi Raymond, from what I remember, all the brown wires should be connected to the battery live post on the solenoid. Now it gets a bit more complicated! How thick is the white and red wire? if it is quite thick then connect it to the large spade on the solenoid, if it is quite flimsy then you will have to wire in a relay. The small terminal on the starter solenoid is used as an additional feed for a ballast ignition coil, and is not usually needed. To test if the starter motor works, short the battery live post with the large spade terminal momentarily and the motor should turn. Hope this is some help !

Gorf

Hi Gorf. Thanks for your post. The white/red is quite thick but it has a standard sized (6.3mm) spade connector on whereas one of the browns has a much larger one so it seems clear where they are supposed to go in this instance. However, I'll keep all that in mind - thanks.

I removed the starter motor today and bridged the terminals. Guess what - Nowt. Zero Zilch. The solenoid is goosed. Whatever the fault is inside it it is resulting in a) no power getting to the switch, dash etc and b) no power getting through to the other side of it to turn the motor. I took it apart to have a look just out of curiosity but there's not much to see and, anyway, I had to bust it a little bit to get into it Inside, there is a short copper strip connected to the small spade and as soon as I touched it with a screwdriver it fell off in my hand so I suppose that's where the problem lay. I have another motor arriving tomorrow so I'll see if that fixes it. Watch this space.....

Today's instalment I collected another starter motor (used but tested and guaranteed) this afternoon and fitted it to my car with exactly the same results as before Oh well, that's another 20 quid down the drain, then.... To make sure that the starter was OK I took it to a local garage where it was confirmed as being fine but something the guy said made me think and I've spent tonight poring over wiring diagrams. My car is 1987 and is obviously intended to take parts from (bodily) clapped out cars which mans that the loom is designed for 1970s cars, I suppose. The engine I have is from a 1990 MG Metro and there seems to be a wiring incompatibility. Eventually, in a diagram in one of my Haynes manuals I found a starter solenoid relay hidden away and things became a bit clearer....maybe Anyway, I have never been able to get power from one side of the solenoid to the other and it seems that I'm missing the relay to do that. It takes a brown wire from the battery side of the solenoid and sends the power back to the other side of it via a brown/red wire which is activated by the white/red from the ignition switch. So, that white/red doesn't go to the solenoid after all - just as Gorf said. I'll try and get a relay tomorrow (it's just a standard 4 pin one) and see what happens - I don't know how the ignition will manage because there's a white and a pink/white wire shown at the solenoid on the diagram and I don't have these. Next time I have my camera in the garage I'll take a photo of my original loom and you can see what I'm up against

Well, fitting the relay solved my problem Thanks for your help Allen anf Gorf The engine now turns over just as it's supposed to but does it start? Does it bug#ery I've been messing around with it this afternoon and it now starts and runs quite nicely but only for about 4 or 5 seconds and then stops as if it's not getting petrol. I've stripped and rebuilt the carb and it's fine so I'm now wondering about the (new) mechanical fuel pump that I fitted because it's a different design from the original and that word 'compatibility' is raising its head again... Oh, it also has oil pouring out of one of the oil gallery plugs and it's not easy to get to. Anyway, here's the original wiring loom....

An attempt has been made to wire in the column stalks from a later car with all the associated relays and fuses. Fair enough but just look at the state of it! Wires have been cut and lengthened or joined to others but there is absolutely no continuity of colour coding and the joints are absolutely terrible. It is totally impossible to follow which wire goes where and the whole thing is a fire hazard but at least it's useful as a source of correct wire if I need any myself. Am I right in thinking that that it's necessary to fit all this if you want the later stalks or is their cabling heavy enough to use without all the relays?