It's in your fuse box. The fuse box on that car is either right beside your hood release or down on the left kick panel.
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It indicates a problem with the airbag. When it's lit the airbag will not deploy.
Should be a reservoir on the firewall driver's side
It means one of your rear brake lights are out. Not the tailights but the brake light(s).
A 1991 Geo Metro convertible typically uses a Group 26R battery. This size is standard for many small vehicles of that era, providing adequate power for the engine and accessories. It's important to check the specific vehicle's manual or consult a parts retailer for the most accurate fit and specifications.
To replace the rear wheel bearings on a 1991 Geo Metro convertible, first, lift the vehicle and securely support it on jack stands. Remove the rear wheel, then take off the brake drum and the retaining clips or bolts to access the bearing hub. Use a bearing puller to extract the old bearings, clean the hub, and install new bearings by pressing them in place. Reassemble by reversing the disassembly steps, ensuring everything is torqued to the manufacturer's specifications.
If by 'controller' you mean the switch that makes the brake lights come on, it is not in the trunk. It is located underneath the dashboard, next to the brake pedal.
in the fuse box
brakes and running lights have separate fuses. check the fuse then check the brake light switch under the dash
The fuse box cover labels them