The EPC light on my daughter's 1.2 , 2010 Fabia recently illuminated and she lost power. She managed to get going again but it happened repeatedly especially after trying to pull away from red lights. We limped the car home and I set to work on trying to find the issue. A quick diagnostics check with a cheap reader showed no codes. I cleaned all the plugs and connectors but the car still lacked power. After some research I checked the brake lights and saw that both the nearside and offside were not working although the one above the tailgate was. I decided to change the brake light switch, which is situated on top of the brake pedal in case it was faulty and had caused a surge resulting in blown bulbs and the EPC light. Both brake light bulbs had indeed blown so I changed these. As soon as I switched the ignition on the EPC light went out and the car is back to full 1.2 power!  Cost of parts, under £20.00. The brake light switch is easy to change. Turn it anti clockwise slightly to take it from it's mount. press the two side clips in to remove the wires and change it over with fitting being the reversal . Leave the brake pedal in it's resting position as you re-fit..Less than two minutes to change. I have posted this in the hope it may help other baffled owners save time and money.

I think there have been previous issues with brake light switches failing causing funny reactions. I am very surprised to see the high brake light working as they often take a feed from one or the other brake lights so if one goes, so does the high one. That might possibly relate more to blown fuses for a side, then just a bulb though. Additionally, if the switch was broken, why would the high level one come on, unless you mean it was just not actually blown.

 

I can only guess that the power loss is either just done "Always" For certain dash lights coming on or otherwise, a deliberate act, to prevent someone driving continually, with no rear lights, as a safety issue. (How often have you seen a leading vehicle with at least ONE blown bulb, often two and even NO rear brake lights)?

 

Fantastic that you found and fixed the issue quickly and economically, though.

Do you actually know that the brake light switch was faulty?

 

A single pole normally open contact switch can not cause a "power surge" to blow a pair of filament bulbs, in any case they are driven by a transistor output within the body control module which recieves a signal input from the brake light switch, its more likely that having both bulbs blown triggered the limp mode, but equally by the same token were that the case a failed switch would also do so.

 

It's implausible that it had failed and blew two bulbs yet the high level light still operated when braking, not implausible that it could fail, its quite common.

 

Thanks for reporting.

 

I think I've read on this site that there was a software update to overcome the car getting the screaming abdabs and going into panic mode if the a brake light area showed a fault.

 

VW and Skoda not quite as clever at programming as they thought, but they did (almost) perfect it for later shenanigans.

 

12 minutes ago, nta16 said:

the screaming abdabs and going into panic mode

 

A simple experiment suggests itself; refit old switch, see if everything stays OK.

I tend to agree with @J.R., two blown bulbs may have been the only faults. 

Edited 10 December, 20214 yr by Wino

Thanks for all your updates on this thread..I cannot say that the switch was definitely faulty but thought it strange that both bulbs blew which with my very minor amount of technical knowledge lead me to suspect a faulty switch causing them to blow . I got a discount on the switch and thought it would be a cheap enough option to change the switch and bulbs in case the switch problem was intermittent as the EPC light and power loss happened a few months previously but seemed to clear itself. I bow to everyone's greater technical knowledge and the suggestion to re-fit the old switch, but if that switch is intermittently faulty it may well work and I suspect I may have already saved well over £100 by not going to a dealer to find and fix the fault so I'm quite happy not to mess with it again.

There are actually two switches in there in the same package, maybe the one that doesn't do the bulbs was the problem. I'm not aware of any way that a mechanical switch can make bulbs blow, more likely just age.

What part number is the old one, please @Albie10, or the new one you bought if the other is already in a bin?

...I get that point, Albie10. I forget how many times I have re-fitted something that I thought suspect, after replacing it, only to re-replace it again as it was defective. (I am always doing that with LED bulbs, etc). As the man once said, "If it ain't broke-don't fix it"!

Its common to have 2 pairs of contacts or two switches, one will operate the brake lights, on our vehicles usually indirectly via the body control module, the other sends a signal to the ECU which it uses to cut the power when the brakes are applied, its for emissions but also safety were the throttle to stick fully open or the output signal doing the same.

 

It prevents me left foot braking over speedhumps when carrying heavy loads and also from bedding in brake pads, on my 95 Galaxy I shunted the ECU contact so it never got the signal because my journeys were always laden over loads of speed humps, after 3 months it generated a fault code "brake switch XYZ123 implausible signal"!!!!

On 11/12/2021 at 15:30, Wino said:

There are actually two switches in there in the same package, maybe the one that doesn't do the bulbs was the problem. I'm not aware of any way that a mechanical switch can make bulbs blow, more likely just age.

What part number is the old one, please @Albie10, or the new one you bought if the other is already in a bin?

The original brake foot pedal switch I took off has a VW mark on it and is part number 6Q0945511. My local dealer hadn't got one in stock and I desperately needed to get the car back on the road so sourced a switch made by Intermotor (Standard Motor Products Europe Ltd) with a main number on the box label 51616. Where is the second switch located?

 

Thanks.

Both switches are in the same item, the outer two thicker wires go to the normally open switch that does the three brake lights, with a (permanently 12V) fuse and the bulbs as the rest of the circuit, plus a connection between output of switch and engine ECU, possibly for bulb monitoring?

 

The inner, thinner wires go to the normally closed switch (fed from a fuse with ignition switched 12V) that goes to the engine ECU as a direct 'pedal pressed' monitor.