Brake warning light

[fast but dim]

Hopefully this is an easy fix...I've used the search

I've just had some welding ( front wheel arches) done by a mate, and picked up the 120. Prior to the work there were no warning lights

The red brake warning light goes off when I release the handbrake, but comes on again after 100m or so.
I've topped up the reservoir, and this hasn't helped.

Brakes work, handbrake works, pads and discs should be ok.

The wheels have been off for the welding.

Could I be missing something simple?

Thoughts?

 

[Rob Cowell]

Just to be clear, the round light with an exclamation mark in it? Is the behaviour consistent? Every time you set off and release the lever the light goes off, then comes on shortly after and stays on? Does wobbling the lever, or pulling it slightly on and off affect the behaviour? My light often flickers but I'm 99% certain its just the handbrake switch thats telling the light whether or not I have the handbrake applied.

 

[fast but dim]

Just to be clear, the round light with an exclamation mark in it? Is the behaviour consistent? Every time you set off and release the lever the light goes off, then comes on shortly after and stays on? Does wobbling the lever, or pulling it slightly on and off affect the behaviour? My light often flickers but I'm 99% certain its just the handbrake switch thats telling the light whether or not I have the handbrake applied.

Yes...the round exclamation mark.

Yes...it's consistent. Light goes off when I release the handbrake, comes on again after a short drive, and stays on. If I turn the ignition off it goes out, but comes on again after a short drive.

Applying and releasing the handbrake while driving doesn't make the light go out.

I've phoned the welder. He's worried that some spatter may have burned through something, but he had everything covered.

I'll have a good luck with the wheels off in the daylight.

 

[fast but dim]

( this forum is so much better than fb)

 

[fast but dim]

The plot thickens....

Drive the cruiser after an MOT pass to work.

Along with the brake warning light being on my cruise control no longer works. The cruise light flashes, but doesn't let cruise engage.

I'm beginning to think a brake or speed sensor (same thing? Has been damaged.

 

[Shayne]

I always disconnect the battery when welding , just in case it causes electrical gremlins , though i've forgot once or twice with no harm done . Maybe disconnecting it for a bit now will reset the confused brains of the outfit .

 

[RichC4]

Could be an abs sensor or wire. Can you plug a code reader in?

 

[Shayne]

MOT station would notice your low on brake fluid - wouldn't they

 

[fast but dim]

I'll try and get the codes read by a mate!
The brake fluid is full...

My money is on a wire to the brakes, but we'll see.

If that fails I'll take the batteries off ( I know they weren't disconnected while welding, unless he re set the clock and tuned the radio)

The lad who welded it has made a right mess. My usual lad was off for an extended break over Xmas, and I took the word of a lad from the pub that he could do it. I'm pissed off.

 

[Shayne]

Wire to the brakes would light up as ABS surely ?

 

[Shayne]

Could be a rusty brake light bulb or something completely unrelated

 

[Rob Cowell]

Flashing cruise control light is the ECU not receiving a speed signal, and should definitely throw an error. Not certain but I think the speed sensor is part of the ABS sensor. But I do think the brake light circuit is involved in there too. The code will tell you which circuit is open.

 

[karl2000]

Along with the brake warning light being on my cruise control no longer works. The cruise light flashes, but doesn't let cruise engage.

Its probably related - the cruise control wont come on because of the brake problem; hopefully once the brake problem is sorted, the cruise will be OK too.

 

[karl2000]

I think if it was a speed sensor you'd have a check engine light? In addition to the ABS wheel sensors, I think theres two speed sensors on the gearbox / transfer case - an input and an output. They all feed eventually into the ECU and need to be working for cruise control to be happy.

If you plug in techstream and look at the live data, you can see the speed from the gearbox sensors (NT and NT2 from memory) and also from each ABS wheel sensor, so you should be able to spot if any of them are not reading correctly.

A dodgy speedo can also cause problems with the speed sensor, as it passes through there before it gets to the ECU.

Parking sensors also tap into the NT2 wire into the ECU and can cause problems if they are knackered!

 

[fast but dim]

Thanks for the replies.
Hopefully I'll.get to the bottom of it!
I'll update this thread when I do!

 

[Higgy]

I think on the 120 if there is an ABS Problem the ABS light comes on, And the red brake symbol should Flash...... I think,... Im sure someone will verify.

 

[AdventureWagon]

I think this light also comes on in the case of low brake servo vacuum. Could a vacuum line or the servo casing be damaged? Might be market dependent if you have one or not (is on the 90)

 

[fast but dim]

I have found the cause of the warning light.

The clown who welded the wheel arches managed to nick the wiring loom with an angle grinder. I'm not happy


Hopefully it's a straight forward job to repair.

 

[Rob Cowell]

For completeness I can tell you (as of this morning) the ! warning light also comes on solid if you pop a brake pipe. Hopefully the balancing valve still means you have some brakes at this point, just much less than you were expecting.

 

[fast but dim]

Update...

It's taken me four months to get to the bottom of this!
Without Paul at West coast off road I honestly think I'd have had to sell the car!

Long story, but in the end it was the lindop tuning box that had shorted out when the loom was cut, and was throwing the throttle position sensor fault!

Paul removed the box, and hey presto...back to normal. No faults, no lights and running perfectly.

Despite being in limp mode for months, the cruiser still drove well enough, which speaks volumes as to how good these cars are!