Hi Tom

I've just been reading about your problem. I'm not sure what's going on with your car, but there's no way your mechanic could take the PCM from another car and use it to start your car, it just doesn't work like that and I'd ask him if he really did it? If you buy used PCM and swap it into your car, it still wont work. Even if you can get a "new" PCM, it wont start your car without being mated up to your immobiliser and coded for your car. If it truly is your PCM, then I'm happy to fix it for you (if you cover the postage, as I live in Australia).

BTW. I have seen cases of the fan running flat out before, and it hasn't been the PCM. Fan controllers usually do this just before they fail completely (some of the soldering inside the fan controllers isn't that good). My suggestion would be replace the fan controller first. Did your Mechanic really try and swap this before and if he did, did he use the exact same type (as they're all coded differently in the PCM)?