• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

brake light failure

Share this page

H

higgins

Senior Member
Country flag
Offline
For some obscure reason my brake lights have failed /bcforum/images/%%GRAEMLIN_URL%%/cryin.gif

The 100/6 has one light for stop light, signal light and tail light. All other lights work fine.

The wires seem to be ok although I haven't had the possibility of checking them from front to back.

The connections also seem to be ok.
Could it be the bulb?

Please help /bcforum/images/%%GRAEMLIN_URL%%/thankyousign.gif

regards
 
Higgins--

It could certainly be the bulb--it could also be an open hot lead or ground, or a failed brake light hydraulic switch (these seem to fail on a 2-3 year cycle for me). You'll have an easier time of it if you have a helper step on the brake while running things down with a circuit tester, though you can always use a piece of wood or whatever wedged between the seat back and pedal. Don't forget to turn the ignition switch on while testing.
 
Higgins -

Do your turn signal lights work? Is it only the brake lights that have failed?

If so, the problem won't be your bulb but either the relay or the brake switch.

Let us know....
 
Hello "Higgins". Are you saying you have "no" brake lights at all, or only one is working?

If you have "no" brake lights check the brake switch mounted on the passenger/right side front frame rail. If one is working check the nonworking side bulb/wiring/socket etc. If the turn signals both sides and front are working, most likely the problem is what I referred to above.

Good luck
 
Hi guys,

yes I have no brake lights at all. Everything else is working fine.
Turn signals and tail lights work, but neither brake light works no matter how hard I step on the brake.

I've just ordered a new switch to make sure. I'll get around to testing the circuit completely tomorrow and I'll let you know

regards
 
The replacement brake light switches tend to fail quickly, if they work at all. I believe VW sells one that will fit and will hold up.
 
Hi Higgins,
Are you feeling lucky? Well are you punk? Say's a famous actor.

I installed 4 replacement switches. They all worked, however....the tail light did not light up until the pedal was fully depressed. Maybe the next brand will work, the next, untill I gave up. Cars behind me would not know I was braking until I was at a stop.

I replaced the stock fluid pressure type with a mechanical switch.

If interested, it is made my Watson's Street Works. Part number L08. Price, $22.00

You can read about it here:
https://www.watsons-streetworks.com/brake_switches.html

PM me and I'll explain in detail how to install. You'll leave your stock switch where it is and install the Watson's switch on your break pedal arm.

Good luck with finding and fixing your problem.
Roger
 
Some of the after market switches require priming prior to installation to get them to work properly Roger.--Keoke
 
Ok Keoke, I'll come clean.
When I said "I" installed the switches, I used "I" losely.
My Healey mechanic bought all the "good" switches from various vendors. He did prime all the switches. We could not get enough pressure in the switch to activate the tail light untill I was almost at the pedals end pressure.

I have a previous post about this.

Thank you for mentioning this though, for it may solve someone elses situation.

Once the mecanical switch was installed, it solved my problem.

Cheers, Roger
 
Well Roger, if your brake petal travels that far it sounds like you still have air in the lines.

OH! I don't know nothin about that big hole in the foot well panel on the passenger's side---Keoke- /bcforum/images/%%GRAEMLIN_URL%%/laugh.gif
 
Keoke, no air in the lines. We bled them. The problem was not pedal travel. The travel was short and good pressure. Switch problem. Once the mechanical switch was installed, break lights came on with just a touch of the pedal.

My input here folks is that my mechanic and I went trough a lot of hydraulic pressure switches. They are known to go bad, as time goes on. The mechanical switch will not. One less thing to worry about. Plus my new switch is completely hidden, if that is of concern. The original switch is still there, just not active. So my car still looks stock/original.
Cheers, Roger
 
Did you keep buying the same switch from the same supplier?

I have replaced a switch on both the BJ8 and the BN1, and they have continued to work without fail for over 40K miles. I think it does depend on the quality of the switch maker as well.
 
AUSMHLY said:
I installed 4 replacement switches. They all worked, however....the tail light did not light up until the pedal was fully depressed. Maybe the next brand will work, the next, untill I gave up.
Click to expand...
 
OK guys,

believe or not,

checked the car last night and first thing I did was I stepped on the brake. Guess what???!!!??? /bcforum/images/%%GRAEMLIN_URL%%/grin.gif


Yes, you guessed right, they worked. /bcforum/images/%%GRAEMLIN_URL%%/banana.gif

Took the car out today and guess again???!!!??? /bcforum/images/%%GRAEMLIN_URL%%/grin.gif


absolutely right, they still work. /bcforum/images/%%GRAEMLIN_URL%%/banana.gif

I am definitely baffled about this one. /bcforum/images/%%GRAEMLIN_URL%%/crazy.gif

Two theories though and I'd like to know if they might hold up:

1) The day the lights failed, it was occasionally raining. Could this have short circuited something?

2) The same day was also a heavy driving day. Could for some reason the brake light switch have failed because the brake fluid was hot???

Just theories I know but I'm keen on figuring out what happened.

This weekend I'm installing a new brake switch just in case and taking the car out for the next rally /bcforum/images/%%GRAEMLIN_URL%%/driving.gif.

regards /bcforum/images/%%GRAEMLIN_URL%%/thirsty.gif

Higgins
 
Hi Higgins,
Your two theories do not seem likely.

Even if the hydraulic pressure switch is working, current "still" has to go through the DB10 flasher relay contacts to get to the stop lights. These contacts are quite delicate & the slightest bit of contamination can cause them to fail. Same with the wiring terminal connections 5, 3, & 7 on the box. Terminals 5 & 7 are associated with the RH stop light, terminals 5 & 3 with the LH stop light.

The "turn signal" portion of the box uses different contacts which have MORE mechanical pressure on them than the "stop" contacts. Thus the "stop" contacts are the more likely to fail.

It's entirely possible that continued operation "self cleaned" the contacts enough to allow proper operation.

If you feel adventurous, you could remove the DB10 cover & VERY carefully clean all of the contacts. This would best be done with the DB10 relay removed. Careful is the operative word.
D
 
Hi Higgins,

When an electrical problem " goes away by itself " , it will
also " come back again by itself ". It is just a matter of
time ! When the brake lights fail to work again, do this;

1.. Open the bonnet, disconnect the wires from the brake
switch on the side of the firewall. Touch the wires
together, ( don't let either wire touch ground ), and look
to see if the brake lights are now working. If they work
when the wires are touched together, then the brake light switch is bad and you should replace it. I would use the one that Roger has mentioned. I also have that kind and it has worked flawlessly and comes on as soon as you touch the brake pedal, unlike most pressure switches that are still working to some extent.

2.. If the brake lights still don't work with the wires touching together, then the relay that Dave is talking about has gone bad and it needs to be replaced. The new one that Moss sells has modern sealed relays inside and the thought is that they should be more reliable because they are more isolated from the effects of moisture and water.

Since you noticed the problem during damp/wet conditions, it is probably a bad relay instead of the brake light switch. I just has to install a new one for a similar problem except that I had only one brake light fail to work, some of the time. I had previously cleaned the relay contact points and that fixed it but only for a few months.

Ed
 
why said:
The two times in 20 yrs my original switch failed, a modest tap with hammer got it working
Click to expand...
/bcforum/images/%%GRAEMLIN_URL%%/savewave.gif

Well Why, it weren't a modest tap with a hammer but I threw mine up against a block wall been working every since. I think ya gotta shock em.- /bcforum/images/%%GRAEMLIN_URL%%/grin.gif Keoke- /bcforum/images/%%GRAEMLIN_URL%%/yesnod.gif
 
higgins said:
OK guys,

believe or not,

checked the car last night and first thing I did was I stepped on the brake. Guess what???!!!??? /bcforum/images/%%GRAEMLIN_URL%%/grin.gif

Yes, you guessed right, they worked. /bcforum/images/%%GRAEMLIN_URL%%/banana.gif
Took the car out today and guess again???!!!??? /bcforum/images/%%GRAEMLIN_URL%%/grin.gif

absolutely right, they still work.
I am definitely baffled about this one. /bcforum/images/%%GRAEMLIN_URL%%/crazy.gif
Two theories though and I'd like to know if they might hold up:
1) The day the lights failed, it was occasionally raining. Could this have short circuited something?

2) The same day was also a heavy driving day. Could for some reason the brake light switch have failed because the brake fluid was hot???

Just theories I know but I'm keen on figuring out what happened.

This weekend I'm installing a new brake switch just in case and taking the car out for the next rally /bcforum/images/%%GRAEMLIN_URL%%/driving.gif.

Higgins
Click to expand...
You didn't say but are you using silicone brake fluid? It has been known to cause premature brake switch failure.

Check the knowledge base for information on how to clean and adjust the brake/turn signal relay. Not hard at all.
 
Johnny, why should Synthetic brake fluid cause the brake switch to fail? or did you mean that the use of Synthetic brake fluid may fail to activate the brake switch.---Keoke-?
 
Back
Top