Partial Alternator Warning light

[Badgervan]

Hi all,

My 88, 2.5Di, Mk3 has started showing a partially lit alternator warning light after the usual blip of throttle to extinguish the light (ie switch from battery to alt running voltage)

The alt is dumping out 14v the batteries are charging and the electrics are all running fine,are there any common causes of this fault?

Cheers

D

[fortyeight]

hi my warning light stays on a while been told its delayed action from split charger

[Badgervan]

hi my warning light stays on a while been told its delayed action from split charger

mine ain't stayin on full brightness on it's only very dimly lit

[Altransit]

It's a fault with one of the diodes in the diode pack leaking back voltage So long as it's charging OK, you could ignore it, but if it bothers you, then change the alternator

[ake]

The problem is that it may start to discharge the battery when the van is sitting switched off

[fortyeight]

have you got an alarm on

[solarman]

Sorry to but in but was wondering what is causing a low charging reading on my van's alternator?The other day i measured my battery and it was showing12.1 volt not running,today i decided to measure the voltage on battery while engine was running and i was gettingb a reading of 12.3,12.4 slowly rising,but i was expecting a reading of 14 .4 ish as an alternator
would be charging at about that voltage,it has been starting okay but i will need to sort it out as it is undercharging as far as i'm concerned,
Solarman.
Forgot to mention thbat i don't hbave an alternator light lit on dashboard which is unusual if it's not chbarging properly.

[ake]

Sorry to but in but was wondering what is causing a low charging reading on my van's alternator?The other day i measured my battery and it was showing12.1 volt not running,today i decided to measure the voltage on battery while engine was running and i was gettingb a reading of 12.3,12.4 slowly rising,but i was expecting a reading of 14 .4 ish as an alternator
would be charging at about that voltage,it has been starting okay but i will need to sort it out as it is undercharging as far as i'm concerned,
Solarman.
Forgot to mention thbat i don't hbave an alternator light lit on dashboard which is unusual if it's not chbarging properly.

How accurate is the voltmeter you are using

[Jim Archer]

And how lok after starting it did you do the check, almost imediately? or after a good run?

If straight after starting it, it takes a while for the alternator to bring the battery back up to fully charged.

Jim

[solarman]

It's a multimeter and yes only checked it while engine is running,will do another check after a long drive see if it makes a difference,thanks,
Solarman

[ake]

It's a multimeter and yes only checked it while engine is running,will do another check after a long drive see if it makes a difference,thanks,
Solarman

Do you have acces to another vehicle that you could check your multimeter on and then you would have readings to compare with

[solarman]

It's a multimeter and yes only checked it while engine is running,will do another check after a long drive see if it makes a difference,thanks,
Solarman

Do you have acces to another vehicle that you could check your multimeter on and then you would have readings to compare with

could check a mate's LDV diesel tomorrow at same time and report my findings,thanks.

[solarman]

well i went to my mates measured his(two batteries in parallel set up) they measured 13.4 volts,switched his engine on charging at 14.4 volts.Measured mine not running 12.3 volts,switched engine on voltage rose slowly again 12.3,12.4,12.5.
Checked altenator belt seemed a bit slack,so we adjusted for belt tightness,measured again while running and a big improvement charging at 13.87 and stopping around the 13.90.I'm happy with this for now,but i'm wondering if there is a voltage diode to stop it charging more than 13.90 or is the alternator still not charging at max voltage?Even with revving the engine it wouldn't charge higher than 13.90 any ideas?
Solarman

[fortyeight]

does the fan belt look worn shiny if so it could still be slipping a bit, or the pully a bit worn, grooved extra shiny would course it to slip

[solarman]

The old fan belt has snapped so i've replaced it for new and the power steering belt at same time,battery appears to be charging well now and reaching 14 volts,
Solarman.