Hiya, this is a bit of a long one I do apologise but I'm at my wits end. I have a ford focus ghia 2007 plate. Bought it in november (had no service history) had a mini service done, had a few things replaced. Had a new alternator fitted in December. Turned out to be faulty, so had another one fitted. Wrong voltage put in! So replaced again in January. No problems until March. The car kept juddering especially doing 40mph+ mechanic took it for a drive found no issues. Run diagnostics, no issues. Air bag light started coming on and off. Was told not an issue until constantly on. First weekend of May, driving to London (87 miles from home) battery light comes on. Managed to get to my mums, called AA they said it's the alternator. Got a mechanic to look at it he said the wiring was loose. He "Sorted it" on the way home the next day it just didn't feel or sound right. Before getting on the M25, the battery light came on again. Mechanic said just keep going. I managed to get 20 minutes from home before the ABS light came on, engine light came on then the car died. AA managed to jump start it. Because it was bank holiday, they didn't look at my car for 2 days. They said they started my car up straight away. Drove it around for a week, they had no problems what so ever, drove perfect in fact. I asked them specifically to look at the alternator and the battery and the connections. I also asked for a full service. They had it for another week. Said they found no faults! Gave me my car back. Exactly a week later, driving 40mph, car starts juddering. Drove for 20 minutes, on the way back, battery light comes on. Does anyone know what can be the problem? I've had 3 different mechanics look now and run diagnostics but nothing is showing up. I don't even think the last mechanic looked at the connections etc. I've honestly had enough. I just want to know what's wrong with my car 😫 any help or advice would be much appreciated :)

Hi,

Do you own a multimeter to do some electrical tests yourself?

Also, I wouldn't pay for a 'full service' yet, that won't make any difference to this fault.

Hiya, they have already done a full service. Charged me £332 and didn't even look at the alternator or battery like I asked 🙄 I am taking my car to a different mechanic on monday.

Ok, do let us know how you get on.

I have seen Mk2 Focus' eat alternators because the wrong type of battery was fitted. (Standard lead acid instead of calcium or silver calcium).

I've also seen cheap new and refurbished alternators that are utter rubbish and would rather buy a good used one from a working car at a breakers yard given the choice now.

So it could be battery or alternator, or both, or as you say it could be a wiring fault. Don't think we can diagnose any further over the internet at this point.

Thankyou for replying :) the alternator that was fitted in January is an unbranded refurbished one. So potentially could be the reason? I will definitely update on Monday.