Guys I need some help here, ST would not start this morning but did after a jump start.

I have noticed for the past month or maybe more that at 5,600 rpm the battery light would flick on but only ever at this rpm. I would have expected it to gradually come on earlier and earlier leading to a flat battery at some stage in the future.

When I put a meter across the battery its 14.8 but dropped to 14.5 when car was running for 15 mins or so. When I reved it to the point where the battery light comes on (5600 rpm) it read 12.5 V .... so I ask you is the battery or alternator shot

 

alternator, but just check your belt is tensioned correctly first though, belt could be slipping on revs causing the alternator not to generate power properly.

 

try the voltage regulator on the alternator

 

alternator

 

If it is on an ST170, then the alternator is regulated by the ECU.

Would check the voltage @ the alternator itself though, as it could be the regulator / ECU causing problems.

 

its an st200

 

Okay, will check for you then.

 

Sounds more like a slipping belt. All the new fords have their alternator regulated by the ECU.

 

Thanks for the replies guys, and yeah its an ST200 alright. Car started fine this morning, the slipping belt theory would be a lot easier to fix than relplacing the alternator as its meant to be a real bugger to get it out.