Volvo Troubleshooting Questions? Ask a Mechanic for Answers ASAP
This sounds like your bulb malfunction indicator is bad. This is tied into the circuit for all the brake lights and is a common failure. I actually keep a spare good one in my toolbox as a quick test unit.
Below is a component location diagram. The part I am talking about is 7/75 and is located in the center dash area behind the ashtray. It is a red cylindrical component.
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