Intermittent handbrake Red Fault Light

[Bob D]

Hello any advice on the following would be much appreciated

Ford Focus cc3 2007

The past few weeks I have been getting the handbrake light coming on intermittently while driving. This has been having the following effects:

On the Instrument cluster, when turning left/right the light telling me the indicators are on doesnt work and no clicking noise is heard but externally the indicator lights still work except the small ones on the wing mirrors. On the electronic display the temperature reading just shows dashes instead of the temperature (it usually reads the outside temperature). There are probably other things on the digital display but that's what I can remember at the moment.

The first sign of something being wrong was the remote control unlocking not working one morning. On pressing the remote the fuel cap lock worked but the doors and boot remained locked. After a few presses of the remote button the doors and boot finally unlocked. Since then about 50% of the time the remote key will not work. When it doesn't I can still use the key to get in the car, start the engine and drive normally though the red handbrake light is on. After a while (sometimes 30 seconds, sometimes 30 minutes) the red handbrake light goes off and the indicator light on the dash works again and all is normal. This situation can repeat numerous times during a journey.

I borrowed a friends OBD2 reader and found a code u1900 but this seems to be a Ford genetic fault code and could be pretty much anything, so I got a local garage to test it but of course the handbrake light wasn't in fault and the car was OK. They went through their test sequence and told me that the ECU has got confused. They reset it and all was good for about 3 days now the same thing is happening.

If anyone has any idea what's going on I'd be interested to hear it. The fact that it's the handbrake light that keeps going on and off does it point to a brake fault? If so why would it effect the Instrument cluster and the internal indicator light?

Thx for any responses

[Micro]

u1900 sounds like a canbus fault - normally caused by the connector either being loose / dirty on the back of the instrument cluster, or the actual connector having a bad solder joint/s to the circuit board.

You may be able to verify this by getting the cluster out and moving the connector yourself to reproduce the issue.

Check your brake fluid level just to be on the safe side.

[isetta]

I don't know about the lights on this car, but I know on some cars if the handbrake light stays on when the handbrake light is released it is telling you that the brake fluid is too low in the brake fluid reservoir.

[Tdci-Peter]

11 hours ago, Bob D said:

The fact that it's the handbrake light that keeps going on and off does it point to a brake fault? If so why would it effect the Instrument cluster and the internal indicator light?

The common element here seems to be the MS CAN bus.

This bus links the BCM (aka GEM or passenger fuse box), the Door modules (including locking motors and the repeater lights on the wing mirrors), and the Instrument Cluster (IC). It also goes to the Park aid, seat belt controller (ARS), and radio.

The handbrake switch goes into the BCM, and its status goes via the MS-CAN bus to the IC.

The ambient temperature sensor is wired to the BCM, again over the bus to the IC.

The remote control signals are handled in the BCM, and again go via this bus to the Doors. Same with mirror lights.

Forscan, with a "modified" ELM237 can read the MS-CAN bus, and all the modules on it. It may show some errors.

The MS-CAN bus goes to pins 3 & 11 on the diagnostic connector. With the ignition off (for enough time to power down the bus), a multimeter should read 60 ohms between these two pins. Also, while testing this, I would tap the fascia around the IC, to see if it made any changes. (Connector pin-out widely out on the net, or I can give more details if wanted.)

On a 2007 Focus, the IC is a suspect. 2006 was the prime year for faulty ICs, My car, along with loads of other 2006 cars have had this (on the HS-CAN bus), but it could creep into 2007.

There are some big connectors just in front of the passenger door (if the CC3 is like a normal Focus there), I am sure the MS-CAN bus goes through some of these.

It does sound like an intermittent electrical fault on this bus.

 

[Sr1]

Hi, I have exactly the same issue with my 2007 Ford Focus. Sometimes doesn’t happen for months sometimes can happen three or four times on one journey. Symptoms are that the cluster indicator repeater does not work along with the outside air temperature and the handbrake light stays on sometimes the radio doesn’t work either.

if the front seat  passenger gives a right foot kick under where the wiring loom and multi plug connectors are is this seems to solve the problem, not very technical but it does work.

[isetta]

from my experience you would also be missing the blue high beam warning light . all these are controlled by the 2 MS Canbus wires running between the instrument cluster and the fusebox above the passenger's feet. The fuse box hinges down after undoing 2 screws with your fingers. to give more access it can be unhooked from the hinges which can be a bit fiddly to get out and more so getting back in. there are a load of plugs on top and a couple underneath. Although not 100% certain , I think the offending MScanbus wires are on the underneath. I would release the plugs, inspect and put back in. It could be one very slightly iffy pin which might be ok just by removing and replugging in. 

My experience is based on 2008 mk2.5 focus. don't know if yours will be identical