Newbie - possible issue with a mod

[grayboots]

Hi all, have been trawling the Z forums for a while now, and I have to say this is my favourite. I have a 2003 Sterling Grey 2.5i and absolutely love it. I'll get some pics up soon. No real mods at the mo, spent a fair bit of time fitting my Kenwood KOS A200 FM transmitter (a proper hard wired one) and my Parrot CK3100 (can't drive without one of these).
I have also just done the full circle brake light mod as featured in the 'How To' section and think there may be issue with it. As already noted the tail lights are a fair bit brighter after the mod. I'm sure someone will be better informed than I am, but I reckon the voltage to the tail lights prior to the mod is around 3V and after the mod 6V. My problem is this, if the force brake system activates (i.e. ABS comes in) does the voltage to the brake lights also double for 12V to 24V and consequently blow the bulbs!!

 

[gannet]

no idea

welcome along

 

[pvr]

Don't think there is any voltage change anywhere, i.e. all 12v.

 

[daveg]

I saw somewhere in BMW docs about the force brake system on the Z4.

But then I also read that CJ did some tests and couldn't get it to activate under any circumstances, emergency braking with ABS etc.

Good enough for him is good enough for me :wink:

 

[navid.v]

Hi and welcome

 

[cj10jeeper]

Welcome and let's see those photos

I'm pretty sure that the voltage is dropped to 6v for the sidelights and when brakes applied increased to 12v and the full circle conversion overrides this.

In terms of the brake force it never worked on mine before the mod and believe me I tried a few interesting tests :roll:

While the electronics may reduce voltage it most certainly won't increase it to 24v (or above 12v) so there will be no buld blowing issues.

It has however been pointed out that post full circle the difference between sidelight and brakes is not as distinct, however the centre brake light is the one people see on a low Z4

As with mnay mods you need to make assessment of if you want the before or after set up , look and function.

 

[AlanJ]

Hi and welcome - yes I notice the tail lights brighter after the mod!

 

[grayboots]

Thanks for the replies fellas. cj10jeeper, the tail lights are deffo brighter post mod, but I think the lights look way better as a full circle, and now you have put my mind at rest I will leave the links in place. Thanks.

I must admit I was trying to think of a few ways to make the brake force come into play myself but short of risking a prang couldn't really think of anything safe. Could be an interesting topic on its own.

As for pics, I am typing this at work , so I will get my camera out tomorrow (weather permitting).

 

[paddy wright]

Welcome

 

[Taz]

sorry can't help but welcome to the forum

 

[grayboots]

Hi, just came across this. It maybe answers a few questions.

Rear/brake light
The rear-light and brake-light bulbs are in separate compartments in the left and right light
clusters. When the headlights are switched on, all bulbs in compartments 1 and 3 are
switched on. Those bulbs have a power rating of 21 Watts. For the rear light function, all
four bulbs are controlled by pulse-width modulation. This dims all four bulbs to 5 Watts.
During braking, the light switch centre receives a signal from the brake light switch. The light
switch centre then applies 21 Watts to the bulbs in compartment 1. In that way, the brake
light function is performed.

1. Rear/Brake Lights
2. Turn Signal Lights
3. Brake Force Display Lights
4. Back-up Lights
5. 3rd Brake Light
6. License Plate Lights

Brake Force Display
In order to improve the reaction of other drivers to
an emergency stop, the E85 has a Brake Force
Display system. Its purpose is to reduce the likelihood
of being driven into by the vehicle behind.
The Brake Force Display function will only be
available on the US version at series launch.
If a deceleration of more than 5m/s2 or an ABS
signal is detected, the bulbs in compartment 3 are
activated by the light switch centre. They too then
receive the full 21 Watts of power. In this way, the
brake light plus Brake Force Display function is
performed.

I don't know whether brake force control ever made it to the UK or not, but it appears early cars like my own may well not have this "feature" after all.