Cameron

I've changed the alternator for a brand new one and it is still doing this, any ideas?

graham c

iTrader: (5)

battery the light only comes on with one or the other i can never remeber which way it is tho

Cameron

Thing is its a brand new battery aswell, this is what i dont understand, what power rating should it be?

orionmojo

iTrader: (1)

take the ignition cowling off, and steering wheel so its earier to see, and inspect the fat red wire off the barrel, i think theres 2, you need the fat one. if its damaged or the connection is bad replace it, this could be your problem.

martin24uk

when its running put all the lights on, heater ect and check the volts at the battery
with a meter should read about 13.5volts, if it is sounds like the wire for the
battery lights has a break in it.

hope this helps

graham c

iTrader: (5)

loads of new batterys come faulty so just go some were and let them cheack it its free 13+ volts and the alt is fine

Twins

iTrader: (18)

Could also be the link loom from the starter to alternator

12_Second_rst

iTrader: (1)

as above the thin blue wire from the alternator if its broken or not connected the battery light will stay on, examine it all the way back as they tend to break in the strangest places

martysmartie

iTrader: (1)

The blue wire is an earth from light so if disconnected the light would EXTINGUISH when connected it acts as an earth hence the light comes on, it also does another important job by exciting the field windings, this starts the charge process. When running this has 12V plus from the alt and so now is not acting as an earth anymore, as two lives the bulb will extinguish, unless of course the not charging.

Is the replacement alternator definantly a known good working unit?

If so I would check all earths particually the engine earth strap.

Even with the light on when running the alternator can still work fine in some cases, if so you will have 13V plus at the battery with the engine running, if not it's not charging, it's nothing to do with the battery.

Martin

Cameron

This blue wire goes from the alternator to the starter motor?

turbobill

the blue wire goes to the light in the dash i think, theres a thick red wire what goes from the starter motor to the alternator

martysmartie

iTrader: (1)

The blue wire as I say above is an earth for the bulb so it will connect to dash.

The fact the bulb illuminates shows that the blue wire is not a problem, it doesn't extinguish however which does indicate a charging problem, first thing I would do is check the output at the battery with the engine running, if +13V then it is actually charging as it is possible to be faulty but still charge ok.

Only other thing it can be is if this blue wire has shorted, again if you disconnect the blue wire from alt and the light EXTINGUISHES this can be eliminated.

Also never overlook the obvious, is the drive belt tight?

Martin

Cameron

Ok i have disconnected the blue wire and started the car, the light is still on, all i have to do now is check for breaks in the cable etc?

Cameron

This is the alternator im using, which connection should the blue wire be on?

martysmartie

iTrader: (1)

Yes check for breaks as you have a SHORT in the cable as with the wire disconnected the light will not illuminate, trace the wire back through the bulkhead and see if it's chaffed anywhere. It should connect onto the D terminal, the B+ is the output to the battery.

You will find if you rev to around 4000RPM it will charge, at the moment it won't be as the bulb is part of the charging circuit.

W is not used this is used for rev counter on diesels or for chokes in some cases.

Have you had the dash out recently as you may of trapped the wire etc?

Martin

Cameron

Yeah ive had the dials out of the car ill go have a quick look see what i can find, thanks for your help.

Jeesy

Hello mates,

I got about the same problem with my ERSTS2 -88. Battery light keeps on glowing red all the time. When I turn the lights, heater, stereo on the light just comes brighter.

I measured it allready and with idle I got 13,65 (lights and heater on) and without ignition 13,02.

I suppose that alternator is ok, so is the thin blue wire from alternator is worn? Any ideas, anyone? Thanks!

Karlos G

iTrader: (4)

Blue wire is a good bet yes.

RobertM

Probably a problem with the thick B+ wire, or the connection on the alternator or battery.
Could also be a problem with the diodes inside your alternator.