How to test rear brake light switch?

[Guest]

So my taillight does not get brighter when I press on either brake. I removed the lens and can see that when the key is on, only one filament is lit. I have gone through the front brake switch, made sure I had the proper working bulb and checked all connections along the way. I understand that the switches and light are linked so any break in the flow can affect it, right? Is there a way to test just the rear brake switch? I know they're only a few bucks for a new one but I'm cheap and impatient so if I can test it so I KNOW it's that switch then I'll replace it. Thanks folks.

Oh, I did have to replace the socket in the light, but I'm pretty confident that I got that wired properly. Lots of pictures and wiring diagram following during the process.

[cowboyup3371]

All you need to do is disconnect the front switch. If it changes then you know the front is the problem. If not, you either have a problem in the back or with the bulb.

[Souske]

Pull the front switch and clean it. Mine had a spider graveyard inside when I got it.

[LarryA_Texas]

If the light doesn't get brighter with either front or rear brake then it's not likely that both switches have failed. But to test the switch all you have to do is check for continuity when you press on the brake pedal. There are two wires coming out of the switch. The circuit is open until you press the pedal and then it closes.

One simple test would be to disconnect the wires coming out of the rear brake switch and jumper between the two wires that they plugged into. That would have the same effect as pressing the pedal. If the light gets brighter, the switch is either bad or not adjusted properly. If it doesn't then you have a problem elsewhere. This wouldn't confirm the operation of the switch but it would at least let you know if the rest of the circuit is correct. You could do this for both the front and rear brake switch.

The new socket has to have a common ground and two leads; one for the brake light and one for the running light. Three wires in all. The other possibility is that all the wires aren't connected or that the bulb is just put in wrong so it's not making contact with both poles.

[apopleptic]

Looks like I was beaten to the chase on this, but I typed it already so hah...

if you have a multimeter it should be pretty easy to test both voltage and continuity at the rear brake switch.
First, set the meter to Ohms.
when the lever for the rear brake is pushed down it pulls a spring which pulls a plunger type switch with two wires coming off of it.
With the multimeter on both of those connections and the brake lever at rest it should read OL or whatever your multimeter uses to indicate open line.
When you press the rear brake lever it should change to a number pretty close to zero.
Once you have checked that the switch is working (or before it doesn't matter) you should test the leads for voltage. when the lever is at rest. one side of the switch should have about 12V the other should have none. when the switch is pressed both sides should have about 12V.
remember to go from the wire to the battery for a good reading.
Let me know if that gets it for you.