Hello

Looking for some advice. I have a ford fusion 2005 Tdci, about a month ago the battery warning light came on intermittently after a few hours of driving. I have a cigarette lighter Bluetooth to radio player, which also measures the voltage. Voltage was spiking from 13- 17.5 volts. 

Eventually the dash and speedo started to cut out intermittently.  Firstly the garage replaced the battery which did not solve the problem, then the alternator. This seemed to solved the issue, until today when the battery warning light came on and stayed on. The voltage started spiking again. This was about 2 hrs into a drive. Does anyone have some suggestions about what might be causing this? 

 

21 minutes ago, Stevob12348 said:

... Firstly the garage replaced the battery which did not solve the problem, then the alternator. This seemed to solved the issue, until today when the battery warning light came on and stayed on. The voltage started spiking again...

Hi Stephen, and welcome.

I would suggest that, although the problem was identified (the Alternator went bad), the 'cause', was not. I see the same thing, when someone says "... ah, the Fuse has blown, so I replaced it.". That's all well and good, but the Fuse failed for a reason: it was to protect the components and wiring. Well, it's the same with this, so the question is: why did the Alternator go bad? And if the same thing has happened again, the underlying issue needs to be addressed. Any good Auto Electrician should recognise and understand this concept.

2 hours ago, Stevob12348 said:

Does anyone have some suggestions about what might be causing this? 

Disconnect the smart charge plug from the side of the alternator. The voltage from the alternator with the engine running should be a constant 13.95V (or very similar) when measured at the battery terminals with a multimeter. Do the test and report back your findings and I'll tell you what to check next.

4 hours ago, unofix said:

Disconnect the smart charge plug from the side of the alternator. The voltage from the alternator with the engine running should be a constant 13.95V (or very similar) when measured at the battery terminals with a multimeter. Do the test and report back your findings and I'll tell you what to check next.

Great thanks for the help and replying so quickly. I've measured it with engine running but not under load and smart chart plug disconnected ( the 3 pin . I'm getting a constant 12.55 Volts at the terminals. 

6 hours ago, Rob101 said:

Hi Stephen, and welcome.

I would suggest that, although the problem was identified (the Alternator went bad), the 'cause', was not. I see the same thing, when someone says "... ah, the Fuse has blown, so I replaced it.". That's all well and good, but the Fuse failed for a reason: it was to protect the components and wiring. Well, it's the same with this, so the question is: why did the Alternator go bad? And if the same thing has happened again, the underlying issue needs to be addressed. Any good Auto Electrician should recognise and understand this concept.

Hello, thanks for the welcome.

Yeah I'm a bit disappointed with the garage I use failing to do this, first they changed the battery (which had got a damaged cell) and within 10 mins of picking it up the warning light was back on. Then they replaced the alternator - which had done over 160,000 miles - it did resolve it for a few hundred miles. I've decided to get a bit more clued up on it, in case the new alternator /battery have been damaged by the same issue. 

I had the 2005 tdci, the 3pin control plug had corroded connections to alternator - blew the fuse behind glovebox which caused the bat indicator in cluster to illuminate.

Battery then went flat or too low to run resulting in EAC fail (thats another story), replaced the control plug revealing the wiring to it was rotten... this resolved the issue but a number of months later alternator packed up. I replaced it with a new good quality bosch unit and had no more problems thereafter.... actually battery naturally came to the end of it's life eventually.

12.55v running means alternator isn't right, but this is controlled by the pwm line on the control plug. Should be around 14v when correct.

2 hours ago, Stevob12348 said:

. I'm getting a constant 12.55 Volts at the terminals.

12.55V with the smart charge plug disconnected is far too low. You need at least 13.2V to charge a 12V car battery. Nearly all alternators used by Ford will give the default charging voltage of 13.95V as I listed above.

Since the default (emergency smart charge failure) voltage is only 12.55V I'd conclude you have a failing alternator.

17 minutes ago, unofix said:

Since the default (emergency smart charge failure) voltage is only 12.55V I'd conclude you have a failing alternator.

Great, thanks for your help. I'm guessing a brand new alternator shouldn't be failing like that under normal circumstances. 

8 minutes ago, Stevob12348 said:

I'm guessing a brand new alternator shouldn't be failing like that under normal circumstances. 

If was a brand new unit and not just a refurbished unit then I would not have expected it to fail so soon. Like anything these days, quality is not what it used to be.

I was advised not to opt for a cheaper euro cp alternator etc, both by my mechanic and auo-telectrician who suggested the bosch new unit.

Read lots of bad stories about cheaper recon units. I paid approx £190 and fitted it myself, with no problems thereafter.

On 7/23/2024 at 11:01 PM, unofix said:

If was a brand new unit and not just a refurbished unit then I would not have expected it to fail so soon. Like anything these days, quality is not what it used to be.

Also, I completely forgot to reply to this thread when I had this issue last year. This was resolved when the garage realised that they had installed the wrong alternator (in fairness, they didn't charge when they realised this, and it was the suppilier who had made the mistake).