Ford Cortina MkII alternator retrofit

Hello,

Yesterday I was helping a friend replace his alternator in a MkII. He was going from a unit with a built-in voltage regulator to a two-piece setup (alternator + external regulator).

It seems to work - 12V when not running, then the voltage rises when the car is running and tops out at 13.8V when revved.

One problem... There is a blue wire coming from the tachometer that was previously hooked to the old alternator. This appears to be the "Gen" light that would come on to indicate that the alternator was not charging. Any clues on where this would go? We tried the stator and field lugs on the alternator, but neither appeared to work (the light did not come on when the ignition was on but not running).

Thanks!

Charles

Reply to
spork.sporkman
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two-piece

light

There should be a contact on the *control unit* for the warning light IIRC.

Reply to
:::Jerry::::

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember snipped-for-privacy@gmail.com saying something like:

The external regulator should have a connection for the lamp.

Reply to
Grimly Curmudgeon

Interesting, maybe he has the wrong regulator? It has four terminals: "I (ignition lead), A (large post on alternator), S (stator on alternator), F (field on alternator).

Anyone have any pointers to the inner workings of the GEN light, or is it just a lamp?

Reply to
spork.sporkman

the warning light is usually a powered bulb that earths through the alternator to light, it also gives a voltage to 'start' the alternator charging. try putting it to the I connection, it cannot hurt anything in this case.

mrcheerful

Reply to
mrcheerful

Depends. If it's an older Lucas regulator the bulb is a crucial part of the regulator circuit and the wattage rating should be correct, or else it may over-/under-charge. If it's missing, then you get no charge at all. They're usually held in a red plastic holder, when all the other dashboard lights are in white plastic.

Most other regulator makers aren't so rubbish at designing a reliable circuit.

Reply to
Andy Dingley

Think its value ain't that critical - it only has to excite the device. Some lamps have a resistor in parallel so the alternator will still charge if the bulb fails.

Reply to
Dave Plowman (News)

If it's a Lucas ACR, then the _value_ is critical.

If it's most '70s / '80s European stuff, then you need to have a bulb of some sort, but it's not fussy what. If it's French or modern, then it might not need anything.

Reply to
Andy Dingley

I thought acr were regulator built in?

Reply to
mrcheerful

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "mrcheerful ." saying something like:

I think the OP is on about the Lucas AC with external reg. I don't know how critical the bulb value is on those.

Reply to
Grimly Curmudgeon

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