CarlosFandango
New Member
I'm sure that this must have been done numerous times in the past, but I'm darned if I can find any definitive description of how to do it anywhere. As the title suggests, I'm trying to figure out how to replace an alternator warning lamp with an LED. There are a couple of issues it seems: many (most?) alternators require a field current of some apparently indeterminate value in order to work. I believe this is around an amp, but it may be more. Secondly, the voltage difference can be in either direction - [alt high + batt low = battery fault] or [batt high + alt low = alternator fault].
So, giving this some consideration: I'm thinking that the alternator warning lamp itself could be replaced with a power resistor, about ten ohms or so, to supply the field current; a bridge rectifier placed across this resistor could maybe feed an led. But apart from that I'm a bit stumped. I'm on the verge of some practical experimentation... but I've only got one alternator, and my truck needs it!
So does anyone have any pointers to how this might be done, or even better, some actual bona-fide practical experience? I'd be very happy to hear it if you have!
-CF
So, giving this some consideration: I'm thinking that the alternator warning lamp itself could be replaced with a power resistor, about ten ohms or so, to supply the field current; a bridge rectifier placed across this resistor could maybe feed an led. But apart from that I'm a bit stumped. I'm on the verge of some practical experimentation... but I've only got one alternator, and my truck needs it!
So does anyone have any pointers to how this might be done, or even better, some actual bona-fide practical experience? I'd be very happy to hear it if you have!
-CF