Battery Light NOT coming on

[Concerto_Polson]

I had some alternator issues a while back in my '89 Honda Concerto, ended up getting a replacement (second hand) one from another Concerto. Checked the replacement one, replaced the brushes in it whilst it was out, checked everything and it all seemed fine.

It's been in my car for 2ish months and working with no problems. However today I went out to my car, and when I turned the key to "on" the battery light didn't come on. Meaning my alternator is not charging.

I've checked the battery terminals, all good. Checked the connections/plugs at the alternator, all good. Checked the bulb in the dash for the battery light, looked fine but swapped it for a known good one anyway.

Still no battery light, and I now have a flat battery. What the heck could the problem be?

[ChaosMaster]

If the battery is completely flat then no light would come on.... have you got a multimeter? Have you checked the voltage from the alternator when the engine is running? A good will make 14-15v. Your warning light bulb could also have burnt, or a fuse perhaps.

[Concerto_Polson]

Nah I don't have a multimeter, think I'm gonna have to invest in one pretty soon.

The battery isn't completely flat, just flat enough that the car won't start. I checked the warning light bulb, and swapped it for a known good one. Still no change.

I just went to the car, roll started it and it was happy to sit there and idle/run with the battery fully disconnected, but as soon as I turn the headlights on it'll stall. If I reconnect the battery and roll start it again, it'll run, again. I can turn the lights on with the battery connected, but not disconnected.

[Concerto_Polson]

I've checked the circuits and everything as specified in the workshop manual, the bulb ISN'T blown, all fuses are fine. I checked the volts from the battery with a multi-meter, was 13v, but struggled to make 13v. With headlights on it dipped to 11v. Then I checked it again the next day, and the only reading I was getting was 12v. It's not the battery, checked it with another one.

I'm thinking it's time to invest in a brand new alternator, costs around $300 but it'll give me peace of mind for a while. Thoughts?

[grifty]

get yourself a rebuilt one, you exchange your one and the new one comes with warranty aswell, would set you back about $150

I was getting 11.7v on with a few electrics on, the charge light should of come on but it didnt........

[Concerto_Polson]

That sounds like the go, where can I get one from though?

My charge light isn't even coming on when I go to start the car, when the CEL, oil, and brake lights do.

[grifty]

That sounds like the go, where can I get one from though?

My charge light isn't even coming on when I go to start the car, when the CEL, oil, and brake lights do.

dont know why its not showing up on ignition

you should be able to get one from your local spare parts stores, they usually do like rebuild starter motors, cv shafts, p/s pumps etc

[Concerto_Polson]

I don't know of anywhere down here that does that, I'll have to have a look around. Trick will be finding somewhere that actually has an alternator to suit a Concerto.

[grifty]

I dont know about down in TAS but im sure you should be able to find one, I think they are the same as the CRX aswell.

[IV73CI]

sounds like the Voltage Regulator on the Alternator has had its life or is faulty.

try using another working alternator and go from there.

Otherwise a new/reco Alternator shall do the trick.