Brake sensor disabled - MOT failure?

[Pistonpants]

Hi,

When I changed the rear pads on my jag XF and they sent the wrong brake pad sensor, so I cut the wire on the old one and twisted the wires together and taped it up so the warning light doesn’t come on.

Just wondered if this would be an MOT fail? It would be fairly obvious what I’ve done if they look underneath, but also obvious the pads are new.

[M_A_S]

Pistonpants said:

Hi,

When I changed the rear pads on my jag XF and they sent the wrong brake pad sensor, so I cut the wire on the old one and twisted the wires together and taped it up so the warning light doesn’t come on.

Just wondered if this would be an MOT fail? It would be fairly obvious what I’ve done if they look underneath, but also obvious the pads are new.

Not a fail.

[PositronicRay]

M_A_S said:

Pistonpants said:

Hi,

When I changed the rear pads on my jag XF and they sent the wrong brake pad sensor, so I cut the wire on the old one and twisted the wires together and taped it up so the warning light doesn’t come on.

Just wondered if this would be an MOT fail? It would be fairly obvious what I’ve done if they look underneath, but also obvious the pads are new.

Not a fail.

Not a fail, but still unsatisfactory, look at a better repair than "twist n tape"

[E-bmw]

PositronicRay said:

M_A_S said:

Pistonpants said:

Hi,

When I changed the rear pads on my jag XF and they sent the wrong brake pad sensor, so I cut the wire on the old one and twisted the wires together and taped it up so the warning light doesn’t come on.

Just wondered if this would be an MOT fail? It would be fairly obvious what I’ve done if they look underneath, but also obvious the pads are new.

Not a fail.

Not a fail, but still unsatisfactory, look at a better repair than "twist n tape"

On most a short circuit is what brings the warning on, is this one different then?

[Matt_E_Mulsion]

In my experience the warning light illuminates when the circuit is broken.

[paintman]

Matt_E_Mulsion said:

In my experience the warning light illuminates when the circuit is broken.

As E-bmw says, most are caused by the friction material wearing away until the wire of the sensor is able to contact the disc so completing the circuit & putting the light on.
The pads on my RRC have two wires going into the pad which might lead you to believe that the wires need to be fully broken, but once the wire is able to contact the disc the light comes on. Why they have the two wires I don't know.

[Gary C]

paintman said:

Matt_E_Mulsion said:

In my experience the warning light illuminates when the circuit is broken.

As E-bmw says, most are caused by the friction material wearing away until the wire of the sensor is able to contact the disc so completing the circuit & putting the light on.
The pads on my RRC have two wires going into the pad which might lead you to believe that the wires need to be fully broken, but once the wire is able to contact the disc the light comes on. Why they have the two wires I don't know.

Circuit fail sensing, wouldnt be able to tell the plug/wire had failed without it.

Coupled with two level wear sensing

Edited by Gary C on Sunday 27th January 11:04

[PositronicRay]

E-bmw said:

PositronicRay said:

M_A_S said:

Pistonpants said:

Hi,

When I changed the rear pads on my jag XF and they sent the wrong brake pad sensor, so I cut the wire on the old one and twisted the wires together and taped it up so the warning light doesn’t come on.

Just wondered if this would be an MOT fail? It would be fairly obvious what I’ve done if they look underneath, but also obvious the pads are new.

Not a fail.

Not a fail, but still unsatisfactory, look at a better repair than "twist n tape"

On most a short circuit is what brings the warning on, is this one different then?

It won't cause him to crash and burn. It's just a bit of a crap way to fix wires together.

[paintman]

Gary C said:

paintman said:

Matt_E_Mulsion said:

In my experience the warning light illuminates when the circuit is broken.

As E-bmw says, most are caused by the friction material wearing away until the wire of the sensor is able to contact the disc so completing the circuit & putting the light on.
The pads on my RRC have two wires going into the pad which might lead you to believe that the wires need to be fully broken, but once the wire is able to contact the disc the light comes on. Why they have the two wires I don't know.

Circuit fail sensing, wouldnt be able to tell the plug/wire had failed without it.

Coupled with two level wear sensing

Edited by Gary C on Sunday 27th January 11:04

I did wonder it that might be the case, but no lights on when plug disconnected & inside the pad the wires are in a U shape tight together & side by side so it's a one piece wire.

[E-bmw]

PositronicRay said:

E-bmw said:

PositronicRay said:

M_A_S said:

Pistonpants said:

Hi,

When I changed the rear pads on my jag XF and they sent the wrong brake pad sensor, so I cut the wire on the old one and twisted the wires together and taped it up so the warning light doesn’t come on.

Just wondered if this would be an MOT fail? It would be fairly obvious what I’ve done if they look underneath, but also obvious the pads are new.

Not a fail.

Not a fail, but still unsatisfactory, look at a better repair than "twist n tape"

On most a short circuit is what brings the warning on, is this one different then?

It won't cause him to crash and burn. It's just a bit of a crap way to fix wires together.

100% agree with that.

[Gary C]

paintman said:

I did wonder it that might be the case, but no lights on when plug disconnected & inside the pad the wires are in a U shape tight together & side by side so it's a one piece wire.

Does look as if manufactures have done it in many different ways. A some use resistors within the pad, so it can tell if its still intact

[Pistonpants]

Yes, the light goes on when the wires are open circuit (broken) on the jag.

The bit I cut and twisted the wires on is on the £6 disposable plug in sensor which has around 12 inches of its own wire. It’s not part of the main wiring loom and also it was getting dark when I discovered they had sent the wrong sensor so I just wanted a quick fix so I could get it back together. It’s well wrapped in electrical tape so should be ok.

I’m sure I’d read they’d recently changed the rules on the MOT and check the brake pad sensors, but I couldn’t find the article so maybe I’m wrong.

[paintman]

There was a very recent thread on this which I can't find but IIRC the pad thickness warning light is not testable.

[mk2 24v]

There was a brief spell that the warning lamp was a fail. But now it is not part of it, unless the pads are visible and obviously too low

[NotBenny]

whilst it's not "proof", I've had a car go through an MOT like this - wires broke out the pad (no idea how) so I soldered the ends together, put a little heat shrink over it and then secured the now loose bit of wiring out the way - was blatantly obvious the pad wear sensor was no longer working as intended but no brake wear warning was illuminated.