Electrical problems are no more prevalent on the ST220 than most other modern cars, but when they arise they’re usually a pain – and expensive to fix.
Most troublesome of all is the alternator, which is a unique component for the ST220 and lives perilously close to the rear exhaust manifold/cat. Once it fails ( which it will), the charging light on the dashboard will glow, the instruments will do a dance and other electrical goodies will gradually shut down. An ST220 will run for a few minutes without a functioning alternator, after which you’ll need breakdown recovery and a trip to the bank.
A chafed wiring loom can also cause havoc; the loom across the bulkhead contains a fuse that’s not even listed on Ford’s parts diagrams, and if it blows the ST220’s smart- charging system will fail.
Under the bonnet, it’s also vital to check the wiring and operation of both cooling fans, which are known to seize solid; check them by ensuring they run when the air conditioning is switched on.
Other electrical goodies may play up, without such catastrophic results. Reversing sensors ( where fitted) often fail ( or simply need cleaning), as do headlamp washer jets. Heated seat pads commonly stop working ( fiddly to fix), and heated windscreens can have dodgy elements ( costly to replace). Six- disc head units are occasionally problematic, and central locking motors are fragile – exactly the same as other Mk3 Mondeos.