Hi all. My 2002 mk3 mondy smart charge doesn't seem to be working, no idea how long it's been like it but I've only just noticed the other day when I was do some unrelated tests and checked voltage at battery terminals while engine was running; it was only putting 13.6v in when I've read it should be closer to 14.8v (or there abouts), even when revving the engine, voltage seems to be fairly constant around the 13.6v mark. Voltage drops if I put all the electrics on (heater, seats, lights et) and seems to fluctuate around the 12.8/13.2v mark.
I don't have battery light on the dash, nor any fault codes logged according to my code reader. I've checked the alternator fuse (7.5a, I forget the number f30 I think) that was OK, checked the earth points under battery, undid them anyway and gave them a touch up and put them back on, no dice. In the end I decided might as well replace the battery since the one on it was getting a bit old anyway, so I bought a brand spanking new silver calcium hoping my luck would be in. It wasn't.
So I'm left thinking this is the alternator. Its obviously working to some degree but its only putting out the standard "dumb mode" charge, but i've read that the 3 pin plug on the alt can cause this problem too, is that more likely? Best I can tell is on the 3 pin plug, one wire is the 12v supply, one is the pcm control and one is the sense wire. But if one or more was broken wouldn't the battery light come on (as I say mine isn't on, and no fault codes either)?
Edited by heebok, 12 January 2021 - 09:13 PM.