Cheburator

Hi everyone,

my 1984 928 S2 5spd has developed a funny intermittent brake lights warning fault. On startup, I press the brakes pedal and the central warning goes off as it supposed to. However, I get "brake lights" warnings poping up as I drive along. As soon as I touch the brake pedal the warning would go off. Sometimes it would go off by itself...

Any suggestions are more than welcome.

Many thanks in advance,

Alex

Fishy928S4

Is it possible that the silver pin in the bottom of the socket in the tail light assembly has lost it's spring and is just barely making contact with the bottom of the bulb? I had a similar problem in my white S4 and I took the bulb out of the socket and lifted up on the silver pin ( for better contact when bulb was placed back in ) and then placed the bulb back in the socket and it's been fine ever since.

I could be way off, but, I had a problem like that and that fixed it.

jeff jackson

I am confused....does the alarm in your dash say "Stop Lamp"...or does it say "Brake"
if its a Stop Lamp alarm...its a lighting issue triggering the Bulb Check controller to turn on the light...if it says "Brake"...its a whole different set of issues likely causing the light.

Fishy928S4

Isn't there a "stop lamp" and a "tail light" warning? Not sure about one called "brake lights".

jeff jackson

Yes...there one that says "Brake" too...its on the right side of the tach....It usually indicates the Emergency Brake handle isn't fully disengaged, or could indicated low fluid level in the brake master cylinder reservoir (I think)...or is this the light that indicates when the brake pad is excessively worn ? On the Voltmeter and Oil pressure combination gauge, the top 3 warning lights are respectively... Antilock...Brake Fluid...Brake Pad. Then the Bottom 2 warning lights are Park Brake...and Engine Oil....At least thats the case on my S3...If its on the set of Warning Lamps located on the combination instrument indicating Fuel Level, and Coolant temperature...its a Bulb issue...if on the combo imstrument indicating Oil Pressure and Voltmeter...its a Brake System problem

Pfunde

I think "fishy" is on to something - had simular thing due to bad connection

tv

My S2 has the central warning and "parking brake" light come on when i hit a bad bump sometimes, then it goes off in a little while or when i hit another bump. I took apart the hand brake cover and fiddled with the contact there. No change.

Sometime i might have to examine the electrical blueprint to find out how to permanently disable it. The parking brake works but is never used.

jpitman2

Sure its not "Brake Prs" which is when the brake light switches dont fire together and it thinks there is a leak in one circuit...BTDT. This can be a switch problem , which requires replacement in pairs.
jp 83 Euro S AT 50k

Cheburator

Sorry - my bad! It is the stop lights warning. As with regards to the suggestion - bad contact between bulbs and silver springs at the back - I changed both tail lights assemblies last week with new ones hoping that it would solve the problem. Alas, it seems that it is a fault somewhere within the central brain for all the warnings...

Thanks,

Alex

WallyP

If the warning is being set without the brake pedal being pushed, it is more likely to be a faulty connection at the ignition switch or the Central Warning Computer.

If the warning is being set after pushing the brake pedal, it is more likely to be a problem in the brake light circuit or the Bulb Check computer.

jeff jackson

Hey Cheburator...when you changed both tailight assemblies...did you have to pull the rear bumper cover to change them out ??? I was going to do this...but only bought new lenses, as a result of the PITA it is to remove the rear bumper cover to get the tailight housings out. And the paint is peeling a bit inside my tailight housings, so I would have liked to replace them outright.

Cheburator

Hi Jeff,

I did pull the rear PU off to change the clusters. It was not that bad - you have 5 bolts on each side. They are clearly visible inside the rear fenders once you clear a bit of the muck accumulated there. Use a 8mm socket with an extension and you will be done in 1h tops. Be careful and patient with the nuts - they have nyloc and could sometimes rust, so spray them liberally with WD40 or something similar before you start undoing them. I would do the swap by doing one side after the other - makes aligning the PU easier afterwards.

Hope that helps,

Alex

jeff jackson

One more question Cheburator...."Whats a PU" ??? Is that UK translation for Rear Bumper Cover ? I hope so...

Cheburator

Yep, I think it is actually German PU = Rear Bumper Cover

jpitman2

I thought it was just Poly-Urethane....but maybe its german for posterior - something?
jp 83 Euro S AT 50k