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hitman_heron
Damn Electrics...
About 6 months ago, my car, (Mondeo ST200) had the alternator replaced. About 4 weeks ago, the car began electrically playing up, specifically, random dash lights lighting up, (ABS/TC/Oil Light/Battery Light). This only happened when revs were high, say above 5k, and also makes the headlights/interior lights much brighter than normal.
Shortly after, both the headlights blew, (not fuses or relays just bulbs) and were replaced.
On the flip side, the battery light was on, on its own, when the revs were low, below 2k, and consequently headlights/interior lights/dashlights were dimmer than normal.
Everything was normal when revs were between 2-5k.
Screamed to me as some kind of earth fault...checked the main harness and found an earth cable corroded, and was repaired.
After this, the car did not "overcharge" but seemed to "undercharge" at about 3k revs +, with the electrics seeming normal from idle to 3k, and battery light coming on at 3k revs and above.
Found then that an auxiliary belt was slack, and has been replaced, with no change.
Since this, the alternator has been replaced twice, with two different brand new alternators, and still no change.
It was then found the earth cable at the battery end was damaged, and was re-insulated.
Now the problems seems to have reversed, with the battery light on at idle until about 3k revs, with lights dimming etc...after this its fine and all is normal.
Points to add...the battery was metered whilst the engine was running with headlights/beams/air con giving a reading of 13.7V. I've heard its normal between 13.5 - 14.5V?

Any help would be appreciated as im completely stumped now! Considering taking it straight back to a Ford Dealer for a proper check, but can imagine i'll be charged extortionate prices!!

Cheers ... Heron


Right, so an update on this....

Had another mechanic look at it, at has put a "brand new alternator" on it, claiming the one he removed was not new.
Although the problem seems now to be cured, (no dash lights/no batt light), its still not right.
The issue now is the "flickering" of all lights, more specifically a "pulsing" effect, (around 2 pulses per second).
Took it back to the auto electrician who put the latest alternator on, and he summised a problem with the ECU?
I really hope not...
Can anyone offer an opinion; similar problems; possible ideas?

Thanks
SierraYankee99
[quote name='hitman_heron' post='45453' date='Oct 6 2009, 12:08 AM']Damn Electrics...
About 6 months ago, my car, (Mondeo ST200) had the alternator replaced. About 4 weeks ago, the car began electrically playing up, specifically, random dash lights lighting up, (ABS/TC/Oil Light/Battery Light). This only happened when revs were high, say above 5k, and also makes the headlights/interior lights much brighter than normal.
Shortly after, both the headlights blew, (not fuses or relays just bulbs) and were replaced.
On the flip side, the battery light was on, on its own, when the revs were low, below 2k, and consequently headlights/interior lights/dashlights were dimmer than normal.
Everything was normal when revs were between 2-5k.
Screamed to me as some kind of earth fault...checked the main harness and found an earth cable corroded, and was repaired.
After this, the car did not "overcharge" but seemed to "undercharge" at about 3k revs +, with the electrics seeming normal from idle to 3k, and battery light coming on at 3k revs and above.
Found then that an auxiliary belt was slack, and has been replaced, with no change.
Since this, the alternator has been replaced twice, with two different brand new alternators, and still no change.
It was then found the earth cable at the battery end was damaged, and was re-insulated.
Now the problems seems to have reversed, with the battery light on at idle until about 3k revs, with lights dimming etc...after this its fine and all is normal.
Points to add...the battery was metered whilst the engine was running with headlights/beams/air con giving a reading of 13.7V. I've heard its normal between 13.5 - 14.5V?

Any help would be appreciated as im completely stumped now! Considering taking it straight back to a Ford Dealer for a proper check, but can imagine i'll be charged extortionate prices!!

Cheers ... Heron


Right, so an update on this....

Had another mechanic look at it, at has put a "brand new alternator" on it, claiming the one he removed was not new.
Although the problem seems now to be cured, (no dash lights/no batt light), its still not right.
The issue now is the "flickering" of all lights, more specifically a "pulsing" effect, (around 2 pulses per second).
Took it back to the auto electrician who put the latest alternator on, and he summised a problem with the ECU?
I really hope not...
Can anyone offer an opinion; similar problems; possible ideas?

Thanks[/quote]


Sounds like the voltage regulator is shagged. Not cheap to replace but its quite a common problem.
mintalkin
you do not say what year your car is but there is a tsb which covers flickering lights on the v6 engine, it is as follows.


TSB 053/2001

Summary

Should a customer express concern about flickering headlamps, wavering illumination of the instrument cluster, interior lighting and audio unit the probable cause is an extremely high resistance in the battery wiring harness from the central junction box (under the bonnet) to the B+ terminal on the alternator. To rectify the concern an additional cable should be installed.

Part number for this cable - 1133503

Apparently the high resistance from the 7.5A fuse to the alternator multi plug causes it to "pulse" so the new loom does away with this by taking a new feed direct from the main battery cable on the back of the alternator.


this might not be your problem but its worth looking into.


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