Hi guys, I am new to this forum, so please bear with me.

I have searched for info on the problem with my dad's car, but couldn't find anything useful here. My dad owns a 2007 Fiesta 1.6TDCi which suffered a nasty electrical/electronic failure at the end of October 2021 after a battery failure. There is just no response when turning the key to start the engine, even with a new battery installed, yet all the lights in the cluster were still coming on as usual.

The car has been towed to the local Ford agents, but they didn't have the necessary equipment to analyze the problem. The PCM was removed and sent to Ford in Johannesburg, which I think was a waste of time, since they couldn't do anything with it without having access to the car as well. After the PCM was returned to the local agents, the car was then towed to the Ford agents in Port Elizabeth. The PCM was then replaced, but the engine was still not attempting to start. They then said the cluster was also faulty. Since then an auto electrician has worked on the cluster, which apparently had five faults, of which he managed to fix four. So, no progress since then and in the meantime my parents (both in their 80s) are struggling without their car. And I'm living too far away from them to get actively involved in this myself.

Question I have is: how can a battery failure cause both the PCM and the cluster to fail in a way that the engine simply won't start? With no spare cluster available, what other options do they have? Will a cluster from a petrol model work, even though the RPM indication will be much lower down the scale? Obviously the PCB is really what's needed, don't know what the chance is of getting hold of just that.

I really hope someone with the right knowledge could shed more light on this. And if someone on this forum, who is based in South Africa, possibly know of a solution to parts availability, it would be great to hear from you as well.

Hello Dirk, I have seen this problem a couple of times with old model Fiestas. I don't why it sometimes happens but when replacing the battery it can cause a voltage spike that wipes out the security settings in the GEM/BCM and so the car's PATS system no longer recognises the ignition key. Therefore when you try to start the car the PATS will not allow the starter motor to operate or the engine to start.

You can not change the instrument cluster, it is programmed to work only with the GEM/BCM of the car. If you change it then you will cause many more problems.

The security PATS system needs to be re-set and the keys re-learnt. Here in the UK only a full Ford Main Dealer can do this.

There is a couple of You-Tube videos of garages in the UK trying to reprogramme the car but they will not be of any use to you.

The only people that will be able to help is a full Ford Main Dealer.

Check fuse 16 is good (3A)

Hi guys, thanks so much for the replies. The car has been at a main Ford dealer for the last nine weeks, so that already isn't good news. They did bring in an auto electrician to look at it some time ago already, but according to him there is something on the cluster that he couldn't fix, as I mentioned initially. There were four more problems with it that he did manage to fix.