Wiring Diagram - Comments Please

[davidimurray]

On and off for the past few weeks I've been drawing up a wiring diagram for my car. I thought it might be interesting to share it with the forum as it may help some others and I would be interested in any comments and feedback that may help me improve it.

The diagram can be found here - http://rapidshare.com/files/411450614/Roadster_Wiring_V1.xls

Cheers

Dave

[RAYLEE29]

Forgive me if im wrong but the link seems to want me to pay for the download?
am I missing something?
Ray:)

[davidimurray]

When the link opens - there are two 'speedometers'. Below the right hand one it says Free User - click that button. On the next page you will get a download button in the middle of the screen - click it and the download should start.

[tkpm]

This file cannot be downloaded anymore, as there is a limit on downloads.

Which is a shame, as would be very useful to have.

Terry

[davidimurray]

I've tried to do a PDF version that should join together across 4 pages.See attached file.

[twinturbo]

I think the alternator dioed is back to front. ( not 100% on that though )

TT

[twinturbo]

scratch that. I was looking at it the wrong way.

However, I would keep the main charge wire separate from any other +12V wire. Run it from the alternator to the starter and to the battery. Nowhere else.

TT

[gingea1pom]

Cheers Dave

That is just the sort of thing I would like to follow when I get to that stage of my build.:D Nice one.

Cheers Ginge

[baz-r]

the way i see it is looks like it all would work ok but :rolleyes:

seem to notice some of your neg switching circuits are back to front
like hand brake switch.
ie. the feed is live from the ign on sw to the bulb (live all the time) and the h/brake switch earths the bulb completeing the circuit as the switch (earth switched) will only have one wire and saves exsess wiring.
bit like a oil pressure swith say.

this is done because it makes the system fail safe as most of the wiring would be on the neg side and if the insulation was damaged it would make the it go to the warning state.

dont think you need a relay for the horn as most horns are earth switched but thats up to you just copy how the orignal car did it if your not sure

you could use double gang relays say for your headlights (one coil two switchs) and fuse the feed side of the relay

you need to protect the battery side of battery by moving your fuses or by fitting a master fuse i have seen a few cars catch fire! buy poor wiring protection the closer to the battery is always better would be a shame to put all the time and money into your roadster . could even burn the garage/house down

the diode for the charge lamp is this not coverd buy the one in already in the alternator? i would need to check whats fitted

thats my take on it any way :)

[davidimurray]

Thanks for the comments and taking the time to look over the diagrams..

TwinTurbo - The charge light diode confused me for a while and took a few attempts to get right - when I work out which one to use I will add the part number. For the alternator feed I was planning to wire it back to the battery directly. Effectively the circuit would be connected as my diagram -but the physical wiring would be different. I will update the diagram to make it clearer that a dedicated cable should be used.

Ginge - glad I can be some help:) Electrics seem to be one of the areas that isn't documented very well so I thought I would see if I could change that! Once the final diagram is complete feel free to add it as a sticky to the forum.

baz-r - well spotted on the neg switched circuits - must have been asleep when I did those - will correct them and repost. Horns seem a bit of a grey area so I've played it safe - and I figure it gives you an emergency spare in cae you breakdown :p I used twin fuses for a number of the light circuits so that in the event that a fuse blows, you should still have some working lights. Good idea regarding a master fuse - would you suggest putting it where I have marked in the attached pic? In the location I've shown I figure it would cover both the permanent and switched live feeds. Do you have any reccomendations for the type of fuse and rating to fit? I was thinking of something like http://www.vehicle-wiring-products.eu/VWP-onlinestore/fuses/holders2.php I see the Midi fuses are 40-100Amp while the Maxi are 100-250Amp. The extra diode on the charge light is included because some people have had problems with engine run on due to the megajolt continuing to draw power from the charge light after the ignition has been switched off.

Thanks again for all your help guys - and look out for version 2 coming to a forum near you soon :D

[alga]

Thanks David, that's a very clear diagram. And quite usable as a PDF on those 4 pages, too!

[Bonzo]

Nice work David :cool:

I am sure that layout will be very usefull in the not too distant future :)

The PDF works a treat, I look forward to the completed design :)

[davedew]

David,

Just looking at the diagram. Very useful as I to am going to be making my own wiring loom.

One thing I did notice is that you don't have a fuse in the permenant feed for the hazard lights. I think in the original Sierra loom there is a 10a fuse in this feed.

Cheers

Dave

[snapper]

Megajolt has 7.5 amp fuse also check Edis, this should be on a separate fuse.
If the Megajolt fuses or fails the Edis will provide 10 degs advance for limp home

[davidimurray]

Thanks for the further feedback everyone. Wil try and update the drawings soon - I been busy on the car over the weekend and will be tonight so will squeeze in some time soon.

Davedew - must admit I hadn't thought about fusing the Hazards. I think I could simply do this taking a branch off the Horn/fan.

Snapper - as I'm using a hard rev limiter with the Megajolt, the coil power is controlled by the megajolt itself. Hence I figured that if the fuse was to blow to the megajolt, then you would also lose the coil power and you couldn't use the limp home feature of the EDIS module - hence the single big fuse - whether this is the correct assumption - I'm not sure !!??

[davidimurray]

Hello

Here we go - the latest version (V1.1) of the diagram for comment

Modifcations are -

Inclusion of 200A master fuse
Added dedicated alternator supply
Added hazards to fused supply for horn/rad fan
Corrected handbrake/brake fluid light to correct neg switched circuit

Again guys, all comments and feedback gratefully received.

Cheers

Dave

[davedew]

David,

Your going to shoot me.

Just been looking through the IVA manual at the parking light section. I think that you need to swap your ignition switched supply for the sidelights to a permenant supply to comply with the regs.

Cheers

Dave

[davidimurray]

Your going to shoot me.

Nah - that's far to kind :p

Seriously though it's great to have lots of input and feedback from people - better now than in the middle of the IVA test.

On the parking lamp subject (section 30 IVA manual) - I read it as they are optional on vehicles below 6m long and 2m wide, which the roadster is. If you do have parking lamps, then you must be able to turn them on without the key in.

That would suggest we don't need them. What does everyone else think?

[davedew]

Just looked at it again. The table seems to indicate like you say that they are optional on vehicles under 6m long.

Ignore me then. I wont mind, the wife does it regularly!!

Cheers

Dave

[twinturbo]

6M... I thought Class M was just for cars,

I think the longest UK production car was the AM Lagonda at about 17'4" (6M being 20' ! ) well it was when it ceased production in 1990.

TT

[Jimmyd]

David,

This is why I love this forum, thanks for sharing!!!

Only wish I had the knowledge and know how to share.

J

[davidimurray]

Hello Everyone

Well I haven't forgotten about the work in progress - just had a long weekend down in Torquay :)

I've now updated the latest V1.3 of the wiring diagram. Now includes a new relay switched +ve supply.

I've also added a second document - which lists the fuses, relays and wires to the front and back of the car. As always - please have a look over the diagram and the 'equipment list' and if you have any comments please let me know.

[davedew]

David,

Wiring diagram looks spot on. The equipment list is really useful, but I was wondering what size cable you will be using for your main feed to the master 200a fuse, and from there on to the relays & circuit fuses. Supplier info on the equipment list is ideal.

Cheers

Dave

[gingea1pom]

David,

That’s great, thanks for your hard work.

The pdf’s are now saved in my Roadster folder.

Cheers Ginge

[davidimurray]

Thanks for all the kind comments.

As it happens I am currently putting together a shopping list for vehicle wiring products for the various bits I will need. If it is of use to people then I'm happy to post it up here.

Having a quick look at VWP now - I willprobably use the following -
battery to starter - 315/0.40 11.8mm OD, 300 Amp cable
Battery to megafuse - 315/0.40 11.8mm OD, 300 Amp cable

From the megafuse to the fuse/relay box I'm not quite sure what to do yet. If anyone has any ideas it would be much appreciated.

[davidimurray]

A quick thought - would it be possible, or even practical to run battery cable to the fuse box from the megafuse, then split the strands into bundles to go to each fuse spade terminal, then finish off by heatshrinking the lot to cover it all.

Second alternative would be to get something like this
http://www.vehicle-wiring-products.eu/VWP-onlinestore/battconns/photo/pj2.jpg

and then use some trailer cable to go from the distribution box with terminal rings, to each fuse.

[twinturbo]

Look at VWP's modular relay/fuse box.

http://www.vehicle-wiring-products.eu/VWP-onlinestore/relays/sockets.php#box

[davedew]

David,

I would have thought your second option was the best and most professional. Pairing out strands from a bigger cable would be quite difficult to ensure you got enough to carry the current.

I was looking at the vwp catalogue earlier and saw the distribution box that you have pictured. I would have thought if it was mounted on the reverse of the bulkhead under the scuttle it would be fine.

Cheers

Dave

[les g]

Dave
i have been watching your posts with lots of interest
electrics are a bane in my job
so far i think you are one the right track
what i would advise is dont over egg the cake
have a look at say a mk 1 cortina /ANGLIA/ESCORT
WIRING DIAGRAMS APART FROM THE OBVIOUS iva
ADD ONS the roadster is not power hungry
cheers lesg

[David_17]

Just found this thread! Amazing, that's all i can say. That's all the info i've been searching for all evening. Wire sizes and everything! Perfect.

I'd just like to say thanks for sharing, really appreciate it. :cool:

[davidimurray]

Just about to start the wiring at the weekend - having looked over the diagram and picked up a new fusebox I have spotted a way to ease the wiring. I have moved the fuses for the fuel pump and ignition circuits to the other side of the relays so they are on the permanent live side. I have also moved the order of the fuses around in the fusebox so that they are grouped by their feed. The fusebox I bought has a busbar with it that can be cut to size so by grouping the fuses together I can run a single wire to each grouping.

I've attached a copy of the latest diagram along with the fusebox and relay listings.

Cheers

Dave

[davedew]

Where did you get your fuse box from? Do you have a part number or picture of it.

Thanks

Dave

[davidimurray]

I bought one of these -

http://www.polevolt.co.uk/acatalog/info_FBB16U.html

And got one of these busbars to go with it -
http://www.polevolt.co.uk/acatalog/info_3_7911.html

[davedew]

Thanks for the links, most appreciated.

Dave

[flyerncle]

Brilliant work David,I could be losing the plot here but talking of parking lights is it possible to do as VW does and use the indicator switch for them with ignition off.

[davidimurray]

Flyerncle

As originally wired - i.e. if you take the column and wiring out complete - the lights work off the permanent live circuit. I.e. the sidelights will come on regardless of whether the ignition is on or off.

I have made the decision to modify this so that the sidelights will only work with the ignition on. This means that if the car is parked up and anyone 'plays' with it they cannot leave turn the lights on.

I also realised at the weekend that the sames applies to the cooling fan over-ride swithc, which should be fed from the switched live rather than permanent live to stop people messing with it. I will update the diagram to reflect this when I get a chance.

The only items that can be 'switched' on with the ignition off in my circuit is the horn and the hazard lights. Everything else requires the ignition on.

Hope that makes sense.

[flyerncle]

I see what you mean David,in the case of MOT the sidelights must work with ignition off as must hazards and to be honest I have not looked at the IVA regs so it may not be needed.

Cooling fans mostly work independently of ignition as the idea is to reduce the rad temp,cutting the feed would defeat the whole object of cooling the system and could lead to overheating.

Nice work.

[davidimurray]

in the case of MOT the sidelights must work with ignition off as must hazards

The lights on my girlfriends Fiat only come on with the ignition

[flyerncle]

I knew that was coming and thought about it later, and I have tested loads of them unfortunately.

[David_17]

Got my wiring connected to the battery today and the main beam kept coming on with the dipped beam. I spent 2 hours trying to sort it, tracing back the wires, but they all seem to be as per diagram. I unplugged the fog relay and it sorted the problem. Is there more than one type of 5 pin relay? Or could it be the diagram?

Hope someone can help.

Cheers

Dave

[twinturbo]

there are many sorts of five pin relay for varying purposes.



TT

[David_17]

Can someone point me towards the correct type then? I thought they all worked on the same basic principle.

[twinturbo]

What relay have you got?

[David_17]

My relay is one of these

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=230493939634

I'm now also struggling with the flasher relay. It's not flashing, just giving constant 12v :(

[David_17]

Is there a way to test the relays (especially the flasher), as i've been offered a replacement, if its faulty.

[twinturbo]

Have you got the lights attatched to the flasher?

The five pin looks like a normal changeover relay.

TT

[David_17]

I've not got all the lights attatched to a flasher, just the front ones. It's getting a 12v but not flashing???

Also, that's what i thought about the 5 pin, but that's causing problems too :(

[twinturbo]

I seem to recall a problem on my sierra, try connecting another lamp. and see fi the relay begins to flash. In nor mal operation you have the load of 4 lamps (front,rear,side, tell tale)

What have you got connected to what on the 5pin.

TT

[David_17]

The 5 pin one is connected as per the v1.3 diagram in this thread.

I'll try connecting more lights this afternoon :)

[davidimurray]

David

I've got my changeover relay wired up as per the diagram and seems to be working fine using the telltales (haven't fitted the full lights yet). I used the changeover relay (blue one) I found in the ford fusebox. Wiring should be to

With regard to the indicators, I left everything wired up as it was on the sieera column. You need to earth the brown wire from the flasher relay. Then find the indicator wires on the column. Check the colours carefully against the diagrams as I have seen a diagram which you need to hold upside down. Not near the car now but I think grn/blk is the RHS indicator. Connect your lamp up to this wire, and then to your earth and the wire should flash, albeit at a fast rate. Did exactly this on the weekend and it is working fine.

[David_17]

Got the flaher sorted. It was a faulty bulb in the light i was teting it with!

Still no joy with the change over relay yet. I'll have a go at that tomorow

[twinturbo]

Cool, seems odd at first when it does not work.

Modern ones are often a timer relay but these old ones need a load to flip-flop.

TT

[davidimurray]

David, Any luck with the headlight circuit?

I would try pulling out connections 87 from the dip and main beam relays. When you change from sidelights to dip you should be able to hear (and feel if you put your finger on the relay) the relay clicking over, the same should happen when you go to main beam for that relay.

If that's ok then I would check the changeover relay. If you can do a conductivity test, 30 should be connected to 87a when on no lights, sidelights, or dip (just to confirm that is based on continuity not voltage). When you turn the headlights on, the changeover relay should switch, and 30 should now be connected to 87. Make sure that 87 from the headlight relay (not 87A) and 86 are connected together.

Cheers

Dave

[David_17]

Still no luck with it. Think i'll just try a new relay, that's all it can be as far as i can see.

[rapidtornado]

David
Great thread and very useful. I'm in the process of pulling my loom from the doner (2.0i DOHC) and after reading this and a few comments on other threads from TT, I'm really reconsidering using the original loom due to the amount of junk in it that I'll spend days identifying and cutting out.

Can anyone tell me how much the wiring diagram in this thread would change for the 2.0i dohc? I know that the ECU will need to get wired in but can you think of anything else that is not covered in David's wiring diagram?


Cheers
Matt

[davidimurray]

Without knowing the wiring of the DOHC generally the loom will stay the same apart form the last two (ignition and fuel circuits) relay circuits on the last page. TwinTurbo is the man who can probably help you on the specifics of the DOHC ECU

[twinturbo]

All sierra's have a stand alone engine loom, they are connected to the body loom via 3 connectors. the DOHC usualy conforms to the post 90 wiring. the best bet it so remove the engine loom and salvage the plugs that it plugs into.

More details of the plugs ( not totaly complete ) can be found on my website, although it's aimed at people converting to the 24V v6.

TT

[james3004]

What size wire did you use from the mega fuse to Relays/fuses Ect..?