* It's a misreading or misremembering: Double-check the light's actual markings. It might be something similar-looking, like a tire pressure monitoring system (TPMS) light (if equipped), a check engine light (CEL), or another warning light.
* It's an aftermarket addition: The light might have been added by a previous owner for a custom accessory or alarm system.
* It's a faulty light: A malfunctioning light could be illuminating without any actual problem.
To figure out what the light means, you'll need to:
1. Carefully examine the light itself: See if there are any other markings or symbols near the light that might offer a clue.
2. Consult your owner's manual: The manual should detail all the warning lights on your dashboard.
3. Check your vehicle's fuse box: A blown fuse could cause a light to malfunction.
4. Take it to a mechanic: If you can't identify the light, a qualified mechanic can diagnose the problem.
Without more information, it's impossible to say definitively what the "USP" light indicates on your 1999 Ford Expedition.
