Ur brake lights

Benjamino · 23-03-17, 12:23 PM

Anyone know what might be the problem causing my brake lights not working please?

I have checked the fuses - all fine.

I have checked the switch on the pedal and it is functioning although I haven't electrically tested it.

I can't imagine all 4 bulbs have blown!

Cheers

Steve · 23-03-17, 05:44 PM

Check the switch electrically and also the wiring in the connector.

M4rkp · 23-03-17, 06:24 PM

Get a multimeter and check to see if there is a voltage between ground and each of the two wires going into the brakelight switch - make sure you make contact with the metal pin inside.
You should have voltage on 1 of these pins ( even with ignition off) -

If you have no voltage on either pin then you have a fuse issue.

If you have voltage on 1 of the pins try checking the other pin while pressing the brake pedal - if there is no voltage then you have a duff switch.
If you have voltage then goto the rear lights and check to see if you have voltage on the lamp terminal in the light cluster - CHECK THEM BOTH.
If you have no voltage there then there is an air gap between your brake light switch and the light clusters

If you do have voltage then check the contacts are actually making contact with the lamp - failing that your lamps are blown - do a quick continuity check on them - its unlikely that all 4 are blown...

....however - never say never with a UR!!!!

Mark

msh · 23-03-17, 06:38 PM

Quick and easy test is to disconnect brake pedal switch and connect both pins with something.

Hanuman · 23-03-17, 07:52 PM

As mentioned. The simple test is to disconnect the plug on the pedal, and using a wire or paper clip etc, connect the two pins together.

The design of the pedal switch was changed many years ago; new switch as supplied had a different socket. A 'repair/replacement' section of wiring with a different connector was supposedly supplied. I've seen this badly installed, with wires simply twisted together instead of a permanent connection with crimps or soldered/sleeved joints.

In fact, in my own ur, Someone had not even fitted the new connector, instead using badly crimped bullet-crimps.

Benjamino · 27-03-17, 02:49 PM

I think I've got a dodgy switch as I unplugged it and sprayed the contacts with electrical cleaner and then the brake lights worked. Went out for a blast and by the time I had got home they were no longer working!!

I'm guessing a more sever clean up of the contacts may sort it prior to making a purchase!!

msh · 28-03-17, 09:34 AM

It's quite likely the switch can be disassembled and contacts mechanically cleaned and bent in proper shape. Take a look.

Tun · 28-03-17, 11:23 AM

This happened on mine in December, took switch apart bent it back into shape and all OK. Following day it packed up again in traffic. I think the switch was getting hot due to poor contact and the metal was just bending away. Just replaced it in the end with one from Pete Reeve (the one's on eBay appear to have the wrong connector).

Benjamino · 28-03-17, 01:28 PM

Thanks guys.

Is there a specific way of removing the switch as mine seems a little reluctant and I don't want to break it?

Cheers

M4rkp · 28-03-17, 02:20 PM

It should just unscrew from the back of the pedal box.

Its a pretty generic part - ISTR my old A4 (B5 model) had the same switch as my WR

A quick search of the part number 443945515 throws this up.

http://www.ebay.co.uk/itm/BRAKE-LIGH...item2ecac7bdf8

M

23-03-17, 07:52 PM	#5
Hanuman Trickster Classic Audi Club Member Join Date: May 2009 Location: Heckling from the cheap seats, Phnom Penh, KoW Posts: 7,006	As mentioned. The simple test is to disconnect the plug on the pedal, and using a wire or paper clip etc, connect the two pins together. The design of the pedal switch was changed many years ago; new switch as supplied had a different socket. A 'repair/replacement' section of wiring with a different connector was supposedly supplied. I've seen this badly installed, with wires simply twisted together instead of a permanent connection with crimps or soldered/sleeved joints. In fact, in my own ur, Someone had not even fitted the new connector, instead using badly crimped bullet-crimps. __________________ I wish they would keep the damned Chinese away now that I can go home, so that I can enjoy Fish amok and a draught Angkor

28-03-17, 11:23 AM	#8
Tun Grown up member Classic Audi Club Member Join Date: May 2011 Location: Buxton Posts: 745	This happened on mine in December, took switch apart bent it back into shape and all OK. Following day it packed up again in traffic. I think the switch was getting hot due to poor contact and the metal was just bending away. Just replaced it in the end with one from Pete Reeve (the one's on eBay appear to have the wrong connector). __________________ 1988 MB quattro 2012 S4 Avant

23-03-17, 05:44 PM	#2
Steve Grown up member Join Date: Nov 2007 Posts: 355	Check the switch electrically and also the wiring in the connector.

23-03-17, 06:24 PM	#3
M4rkp Grown up member Classic Audi Club Member Join Date: Feb 2013 Location: Sometimes Roberttown - sometimes Surrey Posts: 194	Get a multimeter and check to see if there is a voltage between ground and each of the two wires going into the brakelight switch - make sure you make contact with the metal pin inside. You should have voltage on 1 of these pins ( even with ignition off) - If you have no voltage on either pin then you have a fuse issue. If you have voltage on 1 of the pins try checking the other pin while pressing the brake pedal - if there is no voltage then you have a duff switch. If you have voltage then goto the rear lights and check to see if you have voltage on the lamp terminal in the light cluster - CHECK THEM BOTH. If you have no voltage there then there is an air gap between your brake light switch and the light clusters If you do have voltage then check the contacts are actually making contact with the lamp - failing that your lamps are blown - do a quick continuity check on them - its unlikely that all 4 are blown... ....however - never say never with a UR!!!! Mark

23-03-17, 06:38 PM	#4
msh 4 ring whore! Join Date: Jun 2008 Location: Rucava, Latvija Posts: 3,816	Quick and easy test is to disconnect brake pedal switch and connect both pins with something.

27-03-17, 02:49 PM	#6
Benjamino Grown up member Join Date: Jun 2009 Location: Dronfield, Derbyshire Posts: 116	I think I've got a dodgy switch as I unplugged it and sprayed the contacts with electrical cleaner and then the brake lights worked. Went out for a blast and by the time I had got home they were no longer working!! I'm guessing a more sever clean up of the contacts may sort it prior to making a purchase!!

28-03-17, 09:34 AM	#7
msh 4 ring whore! Join Date: Jun 2008 Location: Rucava, Latvija Posts: 3,816	It's quite likely the switch can be disassembled and contacts mechanically cleaned and bent in proper shape. Take a look.

28-03-17, 01:28 PM	#9
Benjamino Grown up member Join Date: Jun 2009 Location: Dronfield, Derbyshire Posts: 116	Thanks guys. Is there a specific way of removing the switch as mine seems a little reluctant and I don't want to break it? Cheers

28-03-17, 02:20 PM	#10
M4rkp Grown up member Classic Audi Club Member Join Date: Feb 2013 Location: Sometimes Roberttown - sometimes Surrey Posts: 194	It should just unscrew from the back of the pedal box. Its a pretty generic part - ISTR my old A4 (B5 model) had the same switch as my WR A quick search of the part number 443945515 throws this up. http://www.ebay.co.uk/itm/BRAKE-LIGH...item2ecac7bdf8 M