Flashing alternator light

[wessexrfc]

Had this problem almost from the start of ownership but seems to be getting worse. Have a new battery and have had the alternator tested and both are ok. When it flashes it's causing the dash lights to dim and the fuel pump changes pitch so the voltage has to be changing. At a guess I would say it flashes two to three times a second. Could this be wiring or is the alternator fried. No problems with starting and it flashes from cold................. Your thoughts please

[RobP]

I'd guess at fried fuel pump wiring . Have you had yours replaced, upgraded?

[Bill NobleUS206]

wessexrfc said:

When it flashes it's causing the dash lights to dim and the fuel pump changes pitch so the voltage has to be changing.

Hi Paul:
My alt light flickered and lights dimmed often until I implemented the alternator wiring change in Ford/Mercury's Tech Service Bulletin described in MACAGAH's post: http://www.nobleforums.com/showthread.php?t=9487&a... A link to the TSB is in Tills' post in that thread.

The TSB procedure is pretty simple. While doing it, I noticed that the loop wire had worked loose from the alternator, probably adding to the flicker problem. No more light flickering and alt light blips since making the TSB change last year. My lights still dim slightly at idle when alternator rpm isn't enough to maintain 14v, but no more flickering.


Hope this helps you out.

[simonx50]

Mine did the same,had all the wiring checked and replaced

[wessexrfc]

I had the wiring upgraded and the fuel pump replaced when i had the exhaust replace. This was about three years ago, so the wiring might need a revisit and check again.

[M12maniac]

I did the ford 'fix' and it didn't work. I also replaced the alternator and wiring in that area, and that didn't work. I evetually traced the problem to corrosion in and around one of the fuse boxes.

[wessexrfc]

M12maniac said:

I did the ford 'fix' and it didn't work. I also replaced the alternator and wiring in that area, and that didn't work. I evetually traced the problem to corrosion in and around one of the fuse boxes.

That could be my problem, did you find that it was an intermittent fault. I've found with mine on a run, it might start flashing then stop, then 5 mins later start again, it is starting to get on my whiskers!!!!

[M12maniac]

Yes...It was an intermittent fault. Would disappear after driving but would return more and more frequently, until it was pretty permanently flashing. I found ford to be pretty unhelpful, and so was their fix. They admitted in the end that they don't really know what causes it. As I said, we tested the alternator, replaced wiring all over the place, the battery was charging.

Check really carefully in the fuse boxes and all the connectors for errosion. That should sort it.

[Bill NobleUS206]

Good points, Richard.

Paul, it's worth checking your grounds to make sure their tight and not corroded. Also worth adding dielectric grease to all of your wiring harness connectors as you check them. Many are not weatherproof.

While thoroughly checking over my Nob after buying it in 2009, I found that the ground wires from the fuse/relay box in the passender-side foot well were very loose, and causing intermittant dash and headlight flickering. By very loose, I mean that the nut and washer on the ground bold was missing; since my car had only 900 miles on it, I figure that HiTech forgot to install the nut and washer. Putting a nut and washer on the ground bolt partially solved my light flicker problem, and the Ford fix took care of the rest.