Charging relay

[BlakeFourTwenty]

A while ago my alternator sort of went, it was charging the battery enough that it didnt die (was still driving for 2 months) the battery light was on. The weird thing was, the radio wouldnt work, it would get enough power that if i pressed eject or clicked the time button then it would light up, as if the ignition was off, every now and then though the radio would power up and play for 20 or so seconds.

Since then i have fitted a new alternator, but the problem persists. The radio has stopped randomly coming on, but the battery light is still there.
I saw somewhere that when an alternator goes it can blow the charging relay? I have no idea what this is or what it means.
Could this be the problem? how would i go about finding out?
- Car is a 1989 5dr hatch, 1.2 carb.

[Rage]

not too sure on the petrols but my diesel van has a charging relay tucked behind the glove box it's part number is 90320276 just so you know you have found the right relay mine was melted to hell inside. from what i have researched the relay should be the same and i would have thought the location of it would be aswell but it might be different due to yours being petrol and mine being diesel.

[BlakeFourTwenty]

I still cant find the part number for the petrol charging relay, anyone know it?

[Adam]

Nova petrols don't have charging relays. Its all straight wired.

Check the alternator earth cable.

[BlakeFourTwenty]

That'll be why i could find one.
Had a mechanic look at it, he put a new earth going to the negative on the battery, i assume this does the same thing as earthing to the engine?

But he mentioned it might be the charging regulator (not relay)
But these seem to be something that should come with the alternator? or is there an external one i can fit?

And cheers for the help guys :)

[Adam]

Regulator is on back of the alternator

[BlakeFourTwenty]

yeah, there was a little black box on the alternator, but there doesnt seem to be one on the new one?

[meritlover]

did it have a single wire on one end and a tab bolted to the alternator housing?

sounds like a choke/suppressor.

[BlakeFourTwenty]

Yeah it wash a little black bosch box that connected to one of the terminals, think it was the negative.

[meritlover]

that's to stop whine and buzz on the radio. not really required.

[BlakeFourTwenty]

So where is the charge regulator and how would i know if its faulty?

[meritlover]

its internal to the alternator, usually a 3phase rectifier diode which will be connected to the brushes and the field coils.

you test it by use of a scope or a voltmeter. there should be a stable 14.5v (ish) across the rev range and with various loads on such as headlights etc. anything more,less, or unstable means its U/S.

you can buy replacement rectifier and brush units online for a couple of earth pounds.

[BlakeFourTwenty]

It's a brand new alternator, unless its something that could die on the shelf?
Just sick of having no radio and a battery light shining at me, and nobody can agree on what the fault is :/ but the regulator is what most people have said

[mowgli]

if its wired correctly & the battery light is on, then the alternator is faulty. its as simple as that. send it back for test/warranty/repair

[meritlover]

... nobody can agree on what the fault is :/ but the regulator is what most people have said

That's because you havent done any of the tests to give people enough information to diagnose the fault.

I'm sorry if my crystal ball is slightly hazey this morning, but given that the rest of the alternator is just 2 lumps of copper wire the regulator would be the most likely failure.

[BlakeFourTwenty]

if its wired correctly & the battery light is on, then the alternator is faulty. its as simple as that. send it back for test/warranty/repair
An answer i wanted. Thankyou.

[meritlover]

could be a wiring fault. test it and report results.