I am looking at a friend's car for her, it just failed its MOT because the ABS light was showing on permanently. 

 

I have just picked up the car from her and the ABS light is not on, I can't get it to show, even at ignition on. 

 

Apparently it was showing for a couple of months prior to the MOT. 

 

The handbrake light also flickers on and off occasionally, not sure if it's related, and again, I am unable to replicate. 

 

Any ideas where to start, fuses are fine. 

 

Many thanks! 

1 hour ago, Robj1 said:

the ABS light was showing on permanently. 

 

I have just picked up the car from her and the ABS light is not on, I can't get it to show, even at ignition on. 

The most common cause of ABS light being on is one of the wheel sensors going wrong. I might just be a bad connector or broken wire. Or it could be the sensor unit, or the sensor ring mounted in or near the wheel bearing.

The first problem is to narrow it down to one wheel. A Ford specific diagnostic system like Forscan can read the wheel sensor readings, and read any DTCs (error codes) in the ABS unit. It certainly works for the Mk2 Focus, and Forscan will work on a Mk1 Focus, but am not 100% sure it will do the airbag systems on these. But it only costs £16 for the ELM327 adapter if you have access to a Windows laptop.

The ABS light should come on with ignition. Are the bulbs filament bulbs on a 2004 Focus? If so, it is possible it has gone from the extended use. But they are normally LEDs (certainly on the Mk2), with indefinite lifetime.

One person on this site took their car to a garage for an ABS fault. It came back with no light (like your car), and still had the fault. They had tampered with the instrument cluster because they could not fix the ABS fault. Very, very bad indeed!

The diagnostic system will still show any codes even if the light is not working.

Perfect, thank you for the detailed response. 

 

So first plan of action, find out if the bulb has gone. 

 

Is it worth cleaning the circuit board, or it is very unlikely to be the cause in this scenario? 

 

 

Kind regards 

Rob 

30 minutes ago, Robj1 said:

Is it worth cleaning the circuit board, or it is very unlikely to be the cause in this scenario? 

I doubt if dust or light dirt on the Instrument cluster circuit board will be linked to the problem. It may be worth looking for corrosion on the pcb, tracks can get eaten through, and solder joints go bad. That could put the light out. If there is evidence of damp or corrosive residues on the pcb, then clean it with alcohol (meths or IPA) or other proper electronic circuit board cleaner. I do not recommend WD40 or contact cleaner for electronic pcbs.

But the underlying problem is why the light came on, and whether that fault still exists. You could check if the ABS works, mine often comes on when I brake (not hard!) as I pull over to a muddy verge on a narrow road. Braking on a very slippery (but safe!) surface should activate it.

The instrument cluster has little to do with the ABS apart from the indicator light.

You should start with a proper diagnostic using a suitable Ford specific diagnostic system/software. Burning ABS and/or parking brake warning lights are a known problem of the Focus MK1. If there are no DTC codes stored inside the brake control module (ABS module) the problem will almost certainly be caused by the instrument cluster. The PCB of the focus MK1 instrument cluster suffers from corrosion. This corrosion causes the PCB tracks to short circuit. One of the first and most common symptons are the ABS and/or parking brake warning light burning intermittently.

Depending on the severity of the corrosion the instrument cluster can either be repaired (cleaned, repaired and conserved) or needs to be replaced.

10 hours ago, Tdci-Peter said:

I do not recommend WD40 or contact cleaner for electronic pcbs

WD 40 and contact cleaner contains a lubricating oil that is used for just that lubrication. It will leave a residue on the circuit board even though it looks dry proper circuit cleaner (usually in a blue can) evaporates so that there is no residue after cleaning. You can get contact( usually in  a red can) and circuit cleaner from Maplin if you have one buy you like me.

One thing you could check on the handbrake  is that the switch that operates the warning light (just under the gaiter in the car) is actually switching off I found the little operating leaver on the hand break just needed a slight bend to switch it off properly and not flicker as it was just on the edge so to speak

Just want to say thank you to all, cleaned the circuit board and light now comes on and goes off exactly as it should. 

 

Just one issue, all the needles dropped off and positions were not marked. While revs and fuel are not an issue, anyone know the approximate resting place of the speedometer? 

 

I will have to road test against sat nav speed and adjust to read slightly over for her to save any unexpected fines! 

 

School boy error! 

Checked against satnav sat at a constant 40 and the speedo is spot on. 

 

Happy friend. 

 

Thanks all