My C70 convertible light stayed on and would chime every once in a while, the source for my car was the seat switch on the drivers side had broken under the seat. There is a spring attached to a plastic post and the post fail. I attached a wire to the spring and then wrapped it around the round frame tube in back underside of the seat and finally anchored the wire to the side of the seat, after adjusting it by looking at the passenger side seat spring. The light and buzzer went out. THh only warning I can give is that I removed the seat the first time is to be careful as the side impact airbags are in the seat with the impact sensor in the front of the seat. When the plastic anchor on my passenger side broke I was able to perform the same repair without removing the seat.
Henri
The 1991 Volvo brake light relay switch is located beneath the drivers side dashboard. The brake light relay switch will be above the brake pedal.
in the locking mechanism
Built in in the hazard light switch.
On the turn signal indicator arm. Switch on the headlights, make sure the high beam is off, then pull out the rotating light switch.
underneath the brake pedal
It is on a bracket, just above the brake pedal.
same interior switch operates the cargo light/just roll it up until the interior light comes on /thats it
Above your left Knee when you are driving
It is under the dash, just above the brake pedal.
It is mounted on bracket just above the brake pedal.
open trunk lid and locate the trunk light switch.push switch to see if light goes off. if light does not go off, replace switch. if light does go off, adjust switch to where trunk lid operates switch when trunk is closed
check the switch at the top of the brake peddle.