RA40 Celica, Charge light stays on 24/7, but charges at 14V? Random drain of .5 amps?

[Rhyno]

Hi Everyone,

My missus recently purchased a RA40 celica, stock except the basics, however it has had a custom center console which has a cd player built into it.

We purchased it with this problem, I though it was just going to be a fuse or reg/alternator...

It has the 18rc and its charge light stays constantly on when the battery is connected, keys out of the ignition. Checked all fuses, all ok, then threw a multimeter across the bat and measured 12.56 with a slooooow drain down to 12.55 after 10-15 secs. Checked the B+ on the alternator and it was putting out 14V at low revs.

Then I put a clamp meter on the positives leaving the battery, and with the ignition off, 1 of the three wires (the small blue one) is draining a steady .3- .5 of amps...

What could possibly cause this? I'm thinking maybe the wiring is broken to the light? But that doesn't explain the slow drain Maybe a stuck relay... could be the combination of two separate problems... hmmn.

Any help would be appreciated

[JadeEstevez]

I did a modification to my 18R in my RA40 where I put an EA Falcon 85amp Alternator and the charge light stayed on. All I did was rewire the yellow with white stripe wire from the back of the gauges. I can't remember where I rewired them too though, It was either L or B on the Alternator... I'll check tomorrow morning and update. As for the slow draining, I have no Idea, But it could again be crappy wiring. Did the person you buy it from wire up that CD player themselves? They could have messed up and have the CD player draining the battery. If not you never know, it might just be the charge light playing up, Sometimes electronics in cars do some weird shit ;P hehe.

[convertableTA23]

The way i understand it is the charge light has a power supply to it when the ignition is in the on position and the alternator earths the other side of it when it is not opperating correctly (ie, not charging). This power supply is used to energise the windings in the alternator to make it create charge easyer (so it oesn't have to self energise). When the alternator is charging it outputs charge current voltage to this wire, thus meaning no voltage difference accross the charge light so the light is off(you can try it if you want, hook both sides of a light to negative on the battery, doesn't work, hook both to positive, doesn't work). So by that information, either the alternator has an internal circut failure and the supply wire to the dash has somehow become on all the time, or more likely the power supply to the dash has broken/got dammaged and is earthing out and the wire is on the wrong terminal on the alternator. Should be able to trace these wires with a multi meter and find out where the power supply is coming from (alternator or dash side of the light) and work out what is going on from there. I am not an auto electrician though, just going on what i remember from tafe when i was doing my trade a few years ago now, so if i'm wrong please tell me so

[thechuckster]

rhyno: get rid of the externally regulated alternator and replace with EA or Magna alternator and delete the regulator thing bolted to the inner guard.

I also found the wiring between the charge light and the alternator to be suspect so I replaced it from lamp to alternator.

It is possible that whoever wired up the CD player has somehow got permanent power going to the Alt regulator instead if Ign-switched power.

There's a few threads here about upgrading the alternator attached to an 18Rx.

[Rhyno]

Hey Guys,

Thanks for your reply's. My first thought was it must be the CD player, but definately not turning on when the ignition is off... I start pulling the thing apart tommorow and chase the wiring back up the charge light. The wiring in general around the engine bay seems pretty fooked, so I may just find a wiring diagram and redo the whole lot. Since we plan on having this car for the next 2-4 years, may as well just bite the bullet and remove the possibility of any gremlins hiding in the 31 year old wiring.

@ thechuckster, sounds good, will look into this. I was planning on doing this upgrade on my 'rona as it is (soon) to be running a 18rgte. Since there are way more threads on how to do it to a Celica I will start here first, then do the same on the Corona.

I will update when I get this problem sorted, or find more percularitys

Thanks all,

Ryan

[The Witzl]

Hi Ryan,

have a read of my threads in teh FAQ about alternator wiring.
The charge light should be wired as follows:

One side of the charge light = IGN 12+
Other side of the charge light = charge light output on the voltage regulator (or on the alternator of internally regulated alternator)

it could be that someone has accidentally wired 12V+ direct from the battery to the charge light, instead of from IGN 12V+

[convertableTA23]

Hey Witzl, if that was the case, and presuming the alternator is opperating correctly, the light would go off when the engine is running (alternator is charging).

[Rhyno]

Ended up dropping a falcon 100 amp alternator in. The old regulator box was completly stuffed and burnt out

Just had to wire up the new alternator after a bit of multimetering and removing the old reg and she worked perfectly

Sorry for the late reply, appreciated everyone's input!