I bought these boots in dec 2015 and they have split down the side just in one boot

Question edited for three uses of the word 'booth', changed to 'boot. As it is a Mondeo, I presume you are in the UK?

Look for a button in the glove compartment that is a child lock and stops the boot being opened from inside the vehicle. The fuse box doesn't show fuses or relays for it. Sometimes there is a slide switch on the inner side of the lock.

Ford Mondeo (2000 - 2007) - fuse box diagram - Auto ...

https://www.autogenius.info > ford-mondeo-mk3-fuse-...
May 25, 2015 - Ford Mondeo (2000 - 2007) - fuse box diagram. Year of production: 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 ...

2000-2007 Ford Mondeo MK3 Fuse Box Diagram

https://knigaproavto.ru > shemy > 477-2000-2007-ford...
Dec 4, 2017 - Fuse Box Layout Ford Mondeo with engine: 1.8L, 2.0L, 2.2L, 2.5L and 3.0L (Mk3 - saloon, liftback, estate; 2000, 2001, 2002, 2003, 2004, 2005 ...

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Check the door weather stripping for leaks. Has this vehicle been in an accident?

if it were me i would just get a new cv axle they went down alot on prices and by the time you **** around putting an after market boot on you will spend about the same money further more usually when the boot is split the bearings are already damaged

Split wrap around boots are not a good option. If your axle joint is in good shape rebooting is an option. It is extremely messy and often takes a special tool to install the new boot clamps. A new axle or a factory rebuilt is always a good option. Beware of local rebuilders they may short cut and not replace all the worn parts.
With the wheel on the ground take off the axle nut, jack up the car, take off the wheel, unbolt the strut, take off the caliper, pull the disc and bearing holder down, and pull the axle out the back side. Pull the axle out of the transmission and take it over to your bench. Remove the inner boot clamps, pull back the inner boot from the transmission bearing cup. There is a large ring clip holding the bearing into the cup , remove the clip and slide the inner cup off of the bearing. With a circlip plier remove the clip from the end of the shaft and slide the inner bearing off of the shaft. Now take the clamps off of the outer boot and slide the boot down the length of the shaft. Clean all of the parts thoroughly and regrease before reassembly. The new boot has to slide down the length of the shaft, from inside to out side, to be installed on the outer joint.

CV joint boot.(cv boot)
It's easier to replace the whole axle , they are cheap in our days.

there or after market replacement boots that are split the length of the axie you cut off the old boot replace with new with out removing axle

It may be the axle shaft boot ring and would have black grease on it, if it is then you need to replace the boot however you can put the emergency brake on and jack up one side at a time and get the tire an inch off the ground and wiggle the wheel up and down if it moves don't drive it have it towed to a repair shop, if it is not loose then try moving the center axle connected to the wheel. if the axle moves from side to side or up or down then the U joint is going out, take it to a shop and get the half shat replaced the shaft costs about $100.00 and the labor about the same, If you can afford it replace them both at the same time. reason you want to replace them both at the same time is so that you keep better fuel mileage if the axle is wobbling it takes more power and fuel to move it. You may be lucky and just need a boot, however unless you get a split boot the axle still has to come out I suggest that you don't use a split boot as they don't stay on very good Hope this helps. The ring if it's off the boot will have slits in it and some tangs on the side it will be the color of aluminum and will be an inch and a 1/2 in diameter or if its the large side it will be about 4 inch's round and about 1/4 wide and about the thickness of a dime.

You need a factory replacement boot...you will need to take the axle out. The easiest method it to buy a new axle and replace the whole thing, but if you want to go the other way, cut the old boot off and clean up the area free from grease. Then pull the axle all the way over to one side and remove the first ball...repeat this until you have all of the ball bearing out. The axle will now come out. You now can place the new boot on and push it back out of your way to repeat the ball bearing process of putting them in one at a time until all is there...you will need a clamping tool to put the new clamps on. Put your new grease in and slide your boots up to the proper place and clamp them on and put the axle back in. You see why I said it is easier to buy a new one, expecially if you have never done this before, but do not use a split boot kit...it won't make it 20 miles and will come apart. OME boot only! Other boots are too soft and will only last 1 year. Good luck!

either buy a split boot kit you can fit it while the shaft is as is in the car,or buy non split type boot and remove CV joint to change (more work)split boot kits are available at auto parts retailers.theyre also well priced

open up the boot on the drivers side and there should be a broken wire or a few broken or split wires in the boot going to the drivers door in the wiring