Alternator Light?

**RAGs** · #1 (**permalink**) 10-04-2007, 10:49 AM

I also posted this on the Electric forum but ...

Once I start my Verde, the Bosch alternator does not seem to begin recharging. Testing the battery shows 12-12.5 - the same as without the car running. It is only after I connect an alligator clip to the positive post, and touch the alternator lead can I "hear" it kick in and volts are up to 13.5 - 15.

As there an alternator light somewhere I'm missing? What else signals the alternator to start charging? Thanks in advance.

**Peter** · #2 (**permalink**) 10-04-2007, 12:53 PM

if you turn your key, but not start yet, does your alternator light go on? I know that at least in the earlier Alfa's the wiring goes through that bulb....if the wiring to the bulb is not complete, or the bulb needs to be replaced, the circuit is not complete and the alternator will not charge

**Craig** · #3 (**permalink**) 10-04-2007, 01:20 PM

As Peter said, In old-school alternators, the warning light is there to provide a tiny bit of current to help make your alternator kick in when you start the car. Power goes from ignition, through the warning light, to the alternator D+ connection, inside to the field coil and then to earth via the regulator. So the chain is Ign -> light -> D+ -> brush -> field coil -> brush -> F terminal -> to regulator -> to earth. If it is an internal regulator , everything from D+ onwards is internal to the alternator.

However, in the Milano/75 the warning light is actually a LED which cannot provide enough current to excite the alternator. This current is now provided by a 56ohm 5watt resistor inside the A.R.C. control box above the tray above the glovebox.

Sometimes this resistor gets hot enough to melt the solder connecting it to the circuit board.

My guess is that this would normally only happen if the warning light was on for a long time but that's just a guess.

**RAGs** · #4 (**permalink**) 10-05-2007, 05:32 AM

Thanks ... I'll take a look this weekend.