Brake lights...
Discussion
Hi all...
very small question...my brake lights are only coming on when I brake very hard, which as you can imagine, is a little scary for other road users
So I went in search of the switch.
Thinking it would be attached to the pedal, I started climbing around in the footwell...no joy there.
After a long search, the only "electrics" I can see connected to the brake system is the little red cap on top of the fluid resevoir, which has two wires coming off of it.
Is this it?
If so how is it adjusted?
Alan.
very small question...my brake lights are only coming on when I brake very hard, which as you can imagine, is a little scary for other road users
So I went in search of the switch.
Thinking it would be attached to the pedal, I started climbing around in the footwell...no joy there.
After a long search, the only "electrics" I can see connected to the brake system is the little red cap on top of the fluid resevoir, which has two wires coming off of it.
Is this it?
If so how is it adjusted?
Alan.
As ditto says, its a line pressure switch. Follow the brake line from rear nearside caliper, switch should be plumbed into the 4 way adapter. Can't adjust so you probably need to replace (will have to bleed brakes after of course). Before this, maybe worth checking brake balance as switch is working off rear brake pressure only. If bias is way off in favour of front brakes, could perhaps cause problem although you'd probably have noticed less than perfect stopping in this case.
It's a common issue caused by two things.
1) The brakes are so damn good you only have to brush them lightly to scrub off speed
2) The position of the switch, on the rear circuit, means that it gets less brake fluid pressure to operate with, as most of the braking bias is on the fronts.
For my Can-Am, I'm moving the switch to be driven from the front circuit.
1) The brakes are so damn good you only have to brush them lightly to scrub off speed
2) The position of the switch, on the rear circuit, means that it gets less brake fluid pressure to operate with, as most of the braking bias is on the fronts.
For my Can-Am, I'm moving the switch to be driven from the front circuit.
bluesatin said:
The brake switch also gradually degrades over time. New switchs always work fine!
You can either replace or fit a different type of switch. The factory spec triggers at 4 bar while the switch I have fitted triggers at 1 Bar!
Aha! Didn't realise a more sensitive version was available. Saves me chopping the loom!
I'm glad this subject has come up because I too noticed, by looking at reflections in the headlights of other cars behind me, that my brake lights where not a very good indicator of me braking.
So a new hydraulic brake light switch is the solution, can we post the make/part no. details to save some hunting around.
So a new hydraulic brake light switch is the solution, can we post the make/part no. details to save some hunting around.
Guy kindly posted me the details.
If you have a look at www.pressureandflow.co.uk , go to Products - Pressure & Vacuum Switches - Industrial - 0166Type.
Switch is part no. 0166-40703-2-027 cost £14.24 ex.VAT and carriage. You'll also need a 1/4" bsp to 3/8"UNF adaptor
>> Edited by Stig on Wednesday 27th October 09:08
If you have a look at www.pressureandflow.co.uk , go to Products - Pressure & Vacuum Switches - Industrial - 0166Type.
Switch is part no. 0166-40703-2-027 cost £14.24 ex.VAT and carriage. You'll also need a 1/4" bsp to 3/8"UNF adaptor
>> Edited by Stig on Wednesday 27th October 09:08
Eliot- that was what I was looking for...shows how long it's been since I got my hands dirty 
Once again thanks to all for all of the excellent info!
I'll get the lighter switch sorted.
I hadn't realised the problem until someone mentioned last week what big b*lls I must have due to the fact that I wasn't apparently braking going into Copse at Silverstone
Of course I didn't argue
Alan.
>> Edited by AlanN on Wednesday 27th October 09:28
Once again thanks to all for all of the excellent info!
I'll get the lighter switch sorted.
I hadn't realised the problem until someone mentioned last week what big b*lls I must have due to the fact that I wasn't apparently braking going into Copse at Silverstone
Of course I didn't argue
Alan.
>> Edited by AlanN on Wednesday 27th October 09:28
Sounds a good idea to have a switch that operates at a lower brake line pressure.
I'm guessing that the reason for failures of the standard part are due to electrical contact failure rather than a failure on the pressure side of the switch. The current rating of the electrical contact will be such that the current drawn by the brake lights exceeds the rating by some margin. I can't find the rating of the standard part but the current drawn by the four brake light units is 6-7 amps.
The part suggested (0166-40703-2-027) has a rating of DC 60w so this will similarly be prone to failure. The solution (whatever the pressure switch) is to use a relay to switch the 6 amp load.
I'm guessing that the reason for failures of the standard part are due to electrical contact failure rather than a failure on the pressure side of the switch. The current rating of the electrical contact will be such that the current drawn by the brake lights exceeds the rating by some margin. I can't find the rating of the standard part but the current drawn by the four brake light units is 6-7 amps.
The part suggested (0166-40703-2-027) has a rating of DC 60w so this will similarly be prone to failure. The solution (whatever the pressure switch) is to use a relay to switch the 6 amp load.
Stig said:
The part suggested (0166-40703-2-027) has a rating of DC 60w so this will similarly be prone to failure. The solution (whatever the pressure switch) is to use a relay to switch the 6 amp load.
Are you sure they're not switched via a relay as they are?
Well, I measured the current through the switch some time ago on my car at 6-7 amps so thats a really large un-necessary relay if one is in circuit!!!!
canam-phil said:
canam-phil said:
The part suggested (0166-40703-2-027) has a rating of DC 60w so this will similarly be prone to failure. The solution (whatever the pressure switch) is to use a relay to switch the 6 amp load.
Are you sure they're not switched via a relay as they are?
Well, I measured the current through the switch some time ago on my car at 6-7 amps so thats a really large un-necessary relay if one is in circuit!!!!
canam-phil said:
I'm guessing that the reason for failures of the standard part are due to electrical contact failure rather than a failure on the pressure side of the switch.
The switch does not fail it just requires more pedal pressure than you use for road use type braking.
Re. electrical load.
Don't the US cars have more lights connected to the brake?
Not allowed here in UK cos rear fog light must be more than ???mm from the brake lights so one set is not used.
Steve
Its the Ultima switch... I have had three so far. The latest one (from ultima) needs only to touch the brake pedel for it to work fine, but also found the connections are a bit flimsy as well. I think they are just crap switchs so a replacement would save everyone a lot of hassle I would suggest.. i think they are off a (old) mini
Gassing Station | Ultima | Top of Page | What's New | My Stuff