1998 Ford Mondeo hazard lights won't stop even when turned off have to disconnect battery,

Not just the hazard switch stuck ? Could try pulling wiring plug / connection from back of switch .

i think it might have something to do with the alarm or central locking, is their a fuse i can pull that won't affect anything else?

Check this , fuse 12 perhaps ? They keep changing depending on models year . Best I can do to help just now , going out .

http://www.btinternet.com/~madmole/Reference/fuses.html

If you think it's tied into central locking / immobiliser , it could be a faulty sensor or door lock sticking . This tells you how to reset key fob remote if you want to try that .


FORD Mondeo 98½> Scorpio 95> (Radio 3 Button) - Key Remote Programming

1. Turn Ignition 4 times from 0 to I, ending at position I. A tone should sound.

2. Press the Remote Unlock button – another tone should sound.

3. Additional Remotes can be added by repeating Step 2, within ten seconds of each remote.

4. To exit turn Ignition to 0 – another audible sound should be made.

and

FORD Mondeo 96> Scorpio > 98 (Radio 2 Button) - Key Remote Programming

Procedure

1. Turn Ignition to II, then turn ignition from II to I and back 4 times within 3 seconds.

2. The PATS LED on dash should light.

3. Turn Ignition to 0. Then press Unlock button and keep it pressed until the PATS LED flashes 4 times (new fob first, then old)

4. Turn Ignition to II, then back to 0 to end.