Brake running lights on 91 Volvo 240 not working---works when breaks applied...changed bulbs and fuse...????

This is also caused by putting the wrong bulb into the socket IE installing an 1156 where an 1157 should be and visa versa. what happens is the bulb acts as a conduit for power to travel into the ground side of the circuit. symptoms of this phenomenon:
depress the brake pedal and the blinkers flash or come on. the dash light come on etc. make sure the proper bulbs are installed. one has even spaced nubs on the bulb the other has uneven spaced nubs. This is also caused by putting the wrong bulb into the socket IE installing an 1156 where an 1157 should be and visa versa. what happens is the bulb acts as a conduit for power to travel into the ground side of the circuit. symptoms of this phenomenon: depress the brake pedal and the blinkers flash or come on. the dash light come on etc. make sure the proper bulbs are installed. one has even spaced nubs on the bulb the other has uneven spaced nubs.