Mk 5 dials in a mk 3

Right kids, listen up - this is my rough guide to fitting Mk5 digital dials into your Mk3 Fiesta.

The guide doesn't cover the actual fitting of the dials into the Mk3 dash - if you're doing that, you can either fit the dials through the back of the dash (i.e. you have to take the dash off) or (more easily) by trimming the bottom of the dials hole in the dash as the locating lugs on the bottom of the Mk4/5 dials foul the mounting tabs on the dash.

First up, you're going to need:
• a set of Mk5 dials. Any ones should do, but the white-faced sport versions are the most popular. Some of the low-end ones (including diesels) don't have rev-counters. They still look good, but there's no real point fitting them, is there...?!
• a metre or so of spirawrap. The best stuff to work with is the smallest version Maplins do (it's about 2mm wide and has a 1mm hole, but you can stretch this out to cover looms up to about 10mm diameter).
• soldering iron
• a metre or two of solder. Use silver solder if you can - it gives a much cleaner joint.
• a box cutting knife to remove insluating tape
• a roll of insulating tape (get the 99p for 5 metres rolls from Maplins, but the ÂŁ1.50 for 1 metre rolls from Halfraud's)
• screwdrivers
• wire stripper/crimping tool
• ring crimp terminals (about 10mm outside diameter) and a male and a female bullet or spade crimp terminal.
• fluffy toy
• assistant to provide endless mugs of tea
• a reel of equipment wire - Maplins do ~15A wire on a 100m reel for around a tenner, which is excellent value and you'll soon use it on other car jobs (if you don't, send it to me - I can always use it!). You can also buy it by the metre if you want - it's about 35p a metre I think.
• lighter or a heat gun to shrink your heatshrink (don't use your soldering iron - you'll scorch it... ouch)
(All the images are clicky, by the way).
You'll also need to work out what all the wires do. I've got a guide here, but I *think* the indicators need to be swapped, and the warning light circuitry needs to be earthed. When I re-do the wiring I will confirm all of this!

The other big problem... - the fuel gauge reads backwards on digital dials. All of them as far as I can tell. You've got two options on this - one is to fit the Mk5 tank sender, and maybe the tank as well depending on whether or not the sender fits the Mk3 tank - or grab yourself a 741IC (small chip, about 30p from Maplin) and a book on 741 circuits to invert the signal. I think swapping the tank will be easier for me, but it's your call!
Next job is to strip the wires back on the multiplug loom but don't solder them just yet. One mistake in this pic - the earths (black) are zapped together. Because of the electronic circuitry, the earths need to be "clean feed" as much as possible back to the chassis - you should extend each individual earth back down to the earth point on the steering column, so add about 2 foot of good (20A) wire to each connection, and crimp (then solder) on a ring terminal to give a good connection. If you cheat like I've done here, then you'll end up with a rev counter that bobs up and down just after starting the car when the battery is slightly low on power, and other weird happenings!

Hokay, next up - remove the dash surround and your old dials. There's a pic here somewhere but it's of my Mk4 dash so it's not really much help. One tip - the speedo cable comes out of the clocks by pushing across on one side of the large plastic ring next to the back of the dials. It doesn't need to be yanked or pulled - when you get it right, it just slides out. Easy money
In this pic I've started removing the spirawrap from my clocks loom - you'll need to cut the insulation tape off your loom. Best thing for this is a box cutting knife with an adjustable blade. Have the knife set so you've only got a mm or two of blade showing, and be careful to run the knife along the wiring, not through it!

You should keep your Mk3 dials plug on the loom for this conversion, so you can swap back to the Mk3 dials if you need to test your wiring, or if something won't work properly. Easy enough to do this: starting with the first wire on your list (which you downloaded and printed off earlier from my site, or worked out from the wiring diags, didn't you? ), make a cut in the Mk3 loom about 4 inches from the multiplug (to allow you some room to manoeuvre) and strip the ends of the wires. If you don't have enough length on the Mk5 loom (you should have a good 6 inches to play with... stop sniggering at the back), extend the wiring with some of your equipment wire. You did buy some, didn't you?
Twist together the bared ends of the wires running to the Mk3 and the Mk5 multiplug, and solder them, then do the same to the remaining wire:

Then put an inch or so of heatshrink over the single wire and push it a few inches up the loom (so it doesn't shrink with the heat of soldering)...

... and solder the wires together:

Then slide your heatshrink over the joint and heat it until it shrinks down nice and tight - the tighter it is, the better. If you haven't used this stuff before, be careful not to overheat one side as you can burn it:

The loom I had was from a boggo fiesta with no rev-counter wire at the multiplug, but it did have a couple of spare pins (listed in the guide I made up) - for example, the traction control light, so I used the multimeter (ÂŁ4.99 from Maplins... God, I need to get a life) to identify a spare pin:

That loom again: pick a wire...

Using a couple of fine screwdrivers or a fine blade (watchmaker's screwdrivers are handy for this), press in the retaining tags on the side of the Mk5 loom, and slide the pin holder out (don't worry, the wires won't all fall out):

Grab the screwdriver or blade again, and press in the retaining tag on the pin you've chosen to use, and pull gently on the wire at the same time to withdraw the wire:

Once the pin is out...

... push it into the rev counter pin hole until the tag engages. If it won't clip it, pull it out (gently) and bend the metal tag out slightly with a fine blade.

If you want the door open warning light to work, you need to tap into the courtesy light loom. I've gone in through the right-hand air vent here...

... but you should drop the car's main loom down from under the steering column and tap into it there if you can. You're looking for a brown wire with a red trace - the easiest way to get to it is to remove the insulation from the loom, find where the wire goes into the door-pin switch and trace the wire back to a suitable location in the loom (e.g. close to where the loom passes under the steering column).
Remove the insulation:

... and strip back the insulation (you should cut the wire if you have enough slack - I didn't have any slack here, and shortening the loom would have made it more likely to break under the strain). Wrap the wire from the door open warning light (which you will need to extend along the existing loom - try to avoid running wires straight across the back of the dash as it makes the loom very messy and hard to manage) around the bared brown/red wire, and tin it:

... then wrap in insulation tape, and tape the loom back up:

Messy... sorry!
Your clocks are going to need a permanent live feed (so it remembers its odometer info) and an accessory (radio) feed (I think...!?). I've taken a feed straight off the ignition loom but remember the ignition loom is unfused and can take around 100A current before it melts. You clock wiring will catch fire much sooner, so add a fuse as close to the joint as possible!

Use your crimp/strip tool to pull the insulation back on the wires you need to tap into (little tip: make two breaks in the insulation about 5mm apart, then use your box knife to cut aliong the 5mm of insluation and peel it off):

Then, like you did with the door warning light, wrap your feed wires around the supply wire (uhhm, you should have disconnected the battery, but just in case you didn't, like me, be careful not to let the wires touch earth or it gets a bit noisy...) and solder, then insulate properly. Again, run the wires along the existing car loom.
Use heatshrink to tape back the old wires:

(Don't cut the wires off - they're handy if you want to add other warning lights to your car, and if you break a pin!).
Right, next up - speedo wiring. Find your speed sensor (injected models only - not got one? Get one from a scrappy's. It needs an ignition live and an earth). Here's the multiplug we're looking for, just to the o/s of the brake servo:

Welcome to my bulkhead. Yours will look a bit like this, but not *quite* the same... You'll be running your speedo wire along here (as well as a rev counter feed if you didn't have one, but I'm not covering that in this guide):

Unscrew the 10mm retaining bolt and lift your header tank out of the way. Undo and remove the insulation tape from one of the rubber nipples on the cable grommer behind the header tank, and pass a feed wire from the clocks through here and along to where your speedo sensor plugs in:

I'm going to say it, but I don't believe for a second you'll do it... you *should* strip the insulation off the car loom all the way along to the centre of the bulkhead, and tape the speedo signal wire in, but if you can't be arsed to do that, at least tuck the wire out of sight
I found that my speedo sensor had dropped a pin, so my car wasn't getting a speed signal to the ECU - not good really. Get the speedo sensor off if you can, so you can give it a clean up. Connect your signal wire to the yellow/black on the speedo sensor-side of the speedo sensor multiplug and add a blade/bullet connection in-line so you can disconnect the wiring if you drop the engine out:

Here's the state of the dash wiring loom:

The speedo cable's tucked out of the way, and the loom needs a hella tidy!
That's better:

Once you're done, plug in and test, take it for a drive, then if you're happy it all works, screw everything up and admire your work!

One nice little trick with these dials: hold the trip button down as you turn the ignition on (it'll reset your odometer though) and you can access the test/data function of the clocks (ignition off and back on to exit). More info here: http://www.fiestaturbo.com/phpBB/viewtopic.php?t=85135
/al

Wiring in the Mk5 clocks

If you are fitting these clocks in a Mk3 dash, you will need to fabricate 4 small brackets to correctly align the 4 screws which hole the clocks in place. The clocks are the same shape as the Mk3 ones they replace.

For this conversion you will need the Mk5 (electronic) clocks, a speed sensor from a Mk5 Fiesta or other late Ford, and the multiplug with a few inches of wire from the back of the clocks. The Mk5 speed sensor replaces the speedo cable at the gearbox end. You can mount this on top of your existing speed sensor if your car is ECU-controlled.

This table lists the wire connections you need to make for the Mk5 clocks on the Mk3 loom.

Note that, like the Mk4 pin numbers, the pin numbers on both Mk3 and Mk5 clocks seem to be a bit random and may not match up to the actual pin numbers, but tracing which connection is which is easy enough.

One problem you may encounter, depending on the loom type in your car, is that the rev-counter may read half (usually HCS and injected CVH engines). If this is the case, you will need to locate a wire in the loom (usually green with a trace or plain green) which pulses on both coil triggers. On injection loom, this is usually one of the green-coded wires passing from the ECU to the E-DIS module.
Mk5 clocks pin Mk5 wire colour Function Mk3 clocks pin Mk3 wire colour Function (same as Mk5 unless stated)
1 Orange Permanent live Create feed from fusebox +ve busbar (7.5A) N/a N/a
2 Violet Ignition switched live 6 Black/yellow N/a
3 N/a Not listed (not used) N/a N/a N/a
4 White/red To ECU (all except n/a diesel) N/a N/a N/a
5 N/a Not connected N/a N/a N/a
6 N/a Not listed (not used) N/a N/a N/a
7 Blue/black LH indicator 2 Black/white N/a
8 Orange/blue Instrument illumination 14 Grey/yellow N/a
9 Grey/violet Systems monitoring (probably goes live if a fault is detected) N/a N/a N/a
10 Blue/black Alternator feed 7 Blue N/a
11 Black/green Oil pressure warning 8 Brown/green N/a
12 Black/blue Handbrake/brake condition warning switch 11 Brown/yellow N/a
13 Black/red ABS circuitry N/a N/a N/a
14 Black/blue Check engine warning light N/a N/a N/a
15 N/a Not connected N/a N/a N/a
16 Black/green Airbag warning light N/a N/a N/a
17 Black Earth 13 Brown N/a
18 White/blue Vehicle speed sensor (remember to connect the VSS black to +ve fused at 3A and the brown to –ve) N/a Brown/white on VSS N/a
19 White To ECU (all except n/a diesel) N/a N/a N/a
20 White/black To Mk4/5 heater controller N/a N/a N/a
21 White/black Rev counter feed 12 Green N/a
22 Blue/white Ignition accessory feed (7.5A fused) N/a Take 7.5A fused feed from ignition yellow N/a
23 Black Earth (join to wiring at pin 17) 13 Brown N/a
24 White/red Fuel gauge sender 5 Brown/black N/a
25 White/red Engine temp sender 4 Brown/white N/a
26 Black/orange Low washer fluid level switch N/a N/a N/a
27 Black Earth (join to wiring at pin 17) 13 Brown N/a
28 Black Earth (join to wiring at pin 17) 13 Brown N/a
29 Blue/yellow RH indicator 1 Black/green N/a
30 Violet/white Main beam indicator 3 Blue/white N/a
31 Black/blue Door ajar warning light N/a Connect to both courtesy light circuits. No special wiring required. N/a
32 White/green To ECU (diesel versions only) N/a N/a N/a
to you, This is the text i copy and pasted to Word before the site hosting it went down: