I've read a lot of posts on here about 240 brake lights not functioning. I have a 1989 240 DL and none of the three brake lights work. All other lights work. I've checked:

• The fuse is good and I get continuity across the fuse
• The bulbs are good
• The brake light switch is good. I get voltage and continuity across the switch terminals.
• I pulled out the bulb failure relay and checked for continuity across all the pins having to do with the break lights

Any other ideas? The only thing I thought might be a little off is that the voltage between the brake light switch terminals is 5V. I would have thought it would be 12V.

 

Find out why it is 5 volts and when you get it to 12 volts the lights should work.

 

one side of the brake switch (the green-red wire) *should* be 12V relative to chassis ground, that comes from fuse 7, the other side goes to the bulb-out sensor, and from the BO it goes to all 3 brake lights on separate wires, and the other side of each brake light goes to ground.