Hi
I have just a few weeks ago replaced the alternator on my car (1998 S-plate Corsa 1.7D) due in the main to the brushes having worn out, but the vacuum pump had cracked and leaked oil all into the alternator.
The replacement unit i used was a reconditioned unit from a highly recommended local vendor/refurbisher. Once installed i observed the voltages with an el-cheapo multi meter and everything seemed tickerty boo :-) if perhaps a tiny bit low on tick over with the glowplugs going :-/ but it seemed to be charging and was fine for a couple of weeks so i was happy.
However in the last couple of days noticed that the alternator does not seem to pumping out sufficent power to charge the battery, last Wednesday the car seemed sluggish to start on the starter, then after 15mins drive refused to start with typical symptoms of low battery, and was still the same following a bumpstart and a couple of hours drive. I charged the battery for 5hours after which the charger was still not showing full, but the car would start.
With the engine running (and the 80amp glow plug fuse removed - they have an after burn phase) i noted that the voltage across the battery was 12.22 volts and rising at around 0.01v per second upto a maximum of around 13v.
If i then Switched on some heavy electical load such as the heated rear screen, the voltage registering on the multimeter would fall away rapidly and there would be no disernable small change in engine note as i can often detect when switching such high loads on. Further, before i replaced the alternator if i had the headlights on and slightly raised the RPM the lights (in common with many cars) would brighten ever so slightly, this no longer occurs, and IMHO they look a bit dimmer.
The "Battery" light is not illuminated.
However, pulling various fuses results in no changes with the exception of one.... Number 17 this is a 15A fuse which according to the legend on the fusebox cover is "KL" i do not have the manual for this car so i am unable to decipher its meaning. However removing this fuse cause all the instruments to go dead, and a relay in the footwell to click in...or out. Acompanying this click is a very slight change in engine note probably a small increase in RPM.
Anyone any ideas what could be amiss here? There are various online referances to a relay that is often found dead following alternator failure on Combo-vans (basically same engine) but this is often connected to the charge lamp staying on.
Kind Regards
Tom Burton