As far as I can tell there are three considerations for choosing the correct instrument cluster to fit in your Transit. The first is how the speedo is driven. Earlier mk5s have a cable driven speedo, akin to the mk1 Mondeo, later mk5s have an electronic speedo, like the mk2 Mondeo. Second is petrol and diesel, make sure you get one to match the fuel type. The diesel revcounter has a D on the dial, and reads up to 6000rpm. The petrol revcounter reads up to 8000rpm.  Third, is the position of certain electronic components on the back of the cluster, some clusters clocks have some kind of component set at the bottom, can't tell you exactly what they do.

As you can see, there are at least 4 types, I picked the 'ESB' cluster, bottom right, which appeared one closest to the non-rev counter cluster already fitted.

Before modifying the cluster, its worth plugging it in to the Transit to check all the lights work correctly. Most will as they are laid out in pretty much the same way. My own cluster gained a 'sidelights on' in the form of a 'front fogs light' icon, which sounds a bit useless as the cluster is lit as well, not to mention the lights-on alarm when you open the door, but it's easier to see during the day. At the same time it lost the trailer warning light, this is not present in the Mondeo cluster, there is a different warning which is wired in a different way and so can't be used (it only works when the alternator warning light and right hand indicator is on).

You also need to check that the wire from the alternator is present in the longer of the two connector blocks. There's a good chance that it isn't there. The wire is grey with a black stripe and starts at the alternator. Follow the cable through the engine loom up to the large twistlock connector block next to the battery. From here you are in the loom that leads through the bulkhead, and the wire is now white with a black stripe. It helps here if you were able to acquire a set of clocks with the connector blocks still in place so you can rob one of the individual connections to put in position a8. Connect the grey/black wire to your new wire in the connector block, and plug the cluster back in.

Turn the ignition on, and check the fuel and temperature gauges move to the same position as your old clocks. Finally, start the engine, and check the reading of the rev counter. It will read somewhere around the 5000-5500rpm mark, and pressing the throttle gently will have the needle going all the way around. This is what the modification will address. The picture below shows Mondeo cluster fitted with a mk6 Transit rev counter, which reads slightly higher at tickover than the Mondeo rev counter. Note the 'D' for diesel below the spindle.

The cluster is quite simple to disassemble. Unplug it all again and find somewhere with a well lit table to work. Looking on the back of the electronic clocks you'll see sets of 3 pins behind the rev counter and speedo, these are their connections to the circuit board. Pop the clear lense off, removed the torx screws holding the speedo and rev counter in the chassis, then gently wiggle first the speedo, then the revcounter, out of the chassis.

On the back of the rev counter is a circuit board populated by a variety of components. R7 is the one to change. On the Mondeo this is fitted with a 370kOhm resistor. This needs to be change to a 0 Ohm chip (as in no resistance, just a link).

Carefully remove the needle and unscrew the face to gain easy access to the chip. Life is much easier here if you have a hot air tool designed to melt the solder on the chip easily, then pull it away with tweezers and replace with the new chip and fresh solder. An alternative is to use a low powered soldering iron (20w maybe) with a flat tip cut into a prong shape to melt the solder on both sides at the same time. Avoid getting too much heat into the board and burning it. Once this is done, refit the face onto the board. Don't replace the needle yet.

If you have a non-contact digital tachometer tool then calibrating the rev counter will easier as more accurate reading can be achieved, otherwise it's a bit trial and error. Either way this part is best done with a hot engine as you need to rev it up. A lot. Using the tacho tool means you and an assistant can do it with less revs.

Fit the cluster back into the dashboard with the connector blocks in place. Gently place the rev counter, without the needle fiited, into the cluster. Start the engine, then lightly replace the needle at around the tickover position. Rev the engine a bit and you will see that the rev counter moves a bit, but not a lot. Pull the rev counter back out and alter R8, the blue adjustable resistor. This alters how far the needle moves when you rev up. Tickover is around 850rpm, and maximum revs is around 4250rpm (check your owners book for actual values), giving a range of around 3400rpm. You need to adjust the blue resistor so that the needle moves the correct amount between tickover and maximum revs. Once you happy with the range, turn the engine off, pull off the needle, then turn the engine back on and refit the needle to give the tickover reading. Rev it up to prove the range. With this done you can rebuild the cluster and refit it.

For the most part the warning lights are in the same positions and work in the same way. There are a few exceptions.

In the picture above you can see a new green light, this comes on with the side lights, but actually the icon is for front foglights. This is going to be altered to come on with the front spotlights. This can't be achieved by modifying the Mondeo cluster so it I am going to fit a bulb in a rubber mount. For now it's going to be used as a lights-on function, many modern cars have this feature anyway.


Similarly, the trailer warning light is replaced with the Mondeo cruise control warning light, the circuit for which is tied into the alternator warning light, and for reasons unknown, the right hand indicator circuit! Don't forget though, the circuit board will  differ as it is in the wrong vehicle. Again this was solved by fitting a bulb in a rubber mount. In anticipation of sucess I had fitted the correct jewel showing the trailer icon to replace the Mondeo jewel.

 

There are other differences too which requires modifications to the circuit board to get working, however I don't need them so I haven't covered them here. The most notable are the ABS light and airbag light which will not function properly without changes. Search the Ford Transit Forum for more on these. Also the cold-start warning light moves from the right-hand side to the left. I don't know if the light would function correctly.