<VV> No Brake Lights

[Frank DuVal]

Comments inserted below:


Borrrris at aol.com wrote:

>OK - this leaves me baffled.
> No brake lights; but taillights and turn signals work  fine.
>  
>

This would be normal if the brake light switch was bad or the fuse 
feeding it was blown.
This would also be normal if the turn signal switch was defective (bad 
contact where the brake light circuit enters the switch).

> Using a continuity probe, verified that output at the brake  pedal switch is 
>good.
>  
>

By continuity probe, do you  mean a tester with a light and a battery? A 
device that will light up if the wire with the clip lead is touching the 
probe? If so, you are using the wrong tester. You need a test light. 
This tester has no battery and requires the circuit under test to 
provide the power. A test light is what you need to troubleshoot with 
the power on.

> Verified that ground at both taillight housings is  good.
>  
>

By how?

> Verified that current at taillamp socket is there when you  press brake 
>pedal.
>  
>

With a test light, DVM, VOM or continuity probe?

> Replaced both bulbs = no difference.
>  
>

OK, not the bulbs. Typically it would not be the bulbs since both brake 
lights are out. But it can happen!

> Removed bulbs and tested for current at sockets under all  scenarios (any 
>combination of tail, turn  and brakes; with light  switch on or off) All test 
>good on the continuity probe INCLUDING BRAKE  LIGHTS.
>  
>

Again, continuity probe or test lamp? If continuity probe, results are 
meaningless with the power on.

> Reinstall the bulbs, and I'm BACK TO NO BRAKE LIGHTS (but  turn signals that 
>use the same wire and same bulb element work  fine.)
>HUH?
>  
>

Since the turn signals are working fine, all the wiring and parts are 
good from the bulbs back to the turn signal switch. Quit looking after 
the switch!

> 
>  
>

Test in order:
1. Fuse for brake lights.
2. Brake light switch. Test by shorting the two contacts together.
3. Turn signal switch. As mentioned in earlier post, the contacts can be 
cleaned if GREAT care is taken working on the internal switch contacts.
4. Since the lamps work with turn signals, no further use looking at 
wiring after the switch. Look at wiring from fuse panel to brake light 
switch to turn signal switch.


Frank DuVal