Handbrake warning light stays on
On most cars the red brake symbol is shared by three inputs: the handbrake lever switch, the brake fluid level float and, on cars with electric parking brakes, the EPB control unit. A light that stays on after the lever is fully released is therefore either a switch that has not opened or a fluid level that is genuinely low. Check the reservoir before anything else, because low fluid usually means worn pads or a leak and that is the dangerous case.
Urgency
Visit a workshop soon
Possible causes, most likely first
- Low brake fluid level
The float switch in the reservoir triggers the same lamp. Look at the level against the MIN mark: low fluid with no leak means the pads are worn thin and the calipers have taken up the volume; low fluid that keeps dropping means a leak. - Handbrake lever switch out of adjustment or sticking
The switch under the lever boot does not open on the last few millimetres of travel. Pull the lever up and let it drop sharply: if the light flickers, adjust or replace the switch; check the wire for chafing at the lever pivot. - Electric parking brake fault
Cars with EPB: the light stays on or flashes, often with a message, when the actuator motor stalls, a cable has stretched or the rear pads are at their wear limit. Read the EPB module codes; actuator current out of range or a position error points to the motor or cable. - Brake pad wear sensor
On some models a worn-pad warning shares or sits next to this lamp. Check the pad thickness through the caliper opening; under 3 mm or a sensor wire that has been ground through confirms it. - Handbrake cable not releasing fully
The lever goes down but the cable or rear caliper lever stays partially applied, which may also hold the switch. Feel both rear wheels after a drive; a hot rear hub and a free lever mean a seized cable or caliper arm. - Wiring short to earth
Water in the connector or a chafed wire grounds the circuit so the lamp is on regardless of lever position. Unplug the lever switch: if the light stays on, the fault is in the wiring or the fluid level sensor. - Brake fluid level sensor faulty
Fluid is at MAX but the lamp is on. Unplug the reservoir sensor and see whether the light goes out; a stuck float or corroded contacts are common on older cars.
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What you can check yourself
- Look at the brake fluid reservoir: is the level at or below MIN?
- Release the handbrake fully, then wiggle the lever and see if the light flickers
- Feel the rear wheels after a short drive for one that is hotter than the other
- Check pad thickness through the wheel spokes on all four wheels