Alternator problem AE92 Corolla

[Peal]

My daughter's 1990 Corolla appears to have a dead alternator, but I'm not positive. Battery voltage is low - 11.2V. I can start the engine with jumper leads, and the voltage keeps going down with the engine running, so obviously the alternator has no output. What is strange is the battery discharge light on the dash doesn't come on under any conditions. This sort of suggests either a blown bulb or wiring open circuit. The charge fuse in the engine bay is fine, as are all the other fuses. Assuming the bulb is blown, does anyone know if this forms part of the alternator circuit - ie does a blown bulb stop the alternator working? From past experience I know alternators tend to fail in these old Corollas, but I hate to buy a reconditioned unit, and find out it is something cheap & simple.

[Rolla Boy]

I don't think the blown bulb would affect the alternator charging...

Easiest way to find out would be to replace the bulb and re-check your alternator charge rate...

[damo101]

if the charge rate is 11.2V there is something wrong with the alternator and i highly doubt that a blown dash bulb is going to cause it to not charge properly.

[Peal]

if the charge rate is 11.2V there is something wrong with the alternator and i highly doubt that a blown dash bulb is going to cause it to not charge properly.

I've taken the alternator out to have checked by an auto electrician. Changing the bulb in the instrument cluster looked too time consuming, but I guess I will have to do this as well.

[Rolla Boy]

It's always good to have all your warning lights working, least that way you'll know if something is wrong and you won't be stranded when the car stops...

[Peal]

It's always good to have all your warning lights working, least that way you'll know if something is wrong and you won't be stranded when the car stops...

Just found this site - http://www.autoshop101.com/forms/h8.pdf

A few other things I should have checked before pulling out the alternator sigh..........

[supertownace]

yes the charge warning light in the dash is a part of the alternator. this light comes on when there is a difference in voltage between the battery and the alternator. having a blown bulb here WILL affect the alternator working. the alternator needs to be "excited" before it will charge a battery. although some alternators will "self excite" under certain conditions.

from what you have described it sounds like the brushes inside the alternator are low and not contacting the slip rings as they should.

these brushes are a part of the alternator that controls how much current the alternator needs to put out. inside the alternator you have 2 major components. those being the stator and rotor. the stator is as the word suggests....stationary and is where the charging current is produced. the rotor is the part that gets turned by the engine via the fan belt. this component is responsible for creating the magnetic field that produces the charging current in the stator. the brushes are the medium used to send a small current to the rotor via a pair of steel or brass rings also attached to the rotor.

hope this helps

cheers

[dorifto]

Hi Peal

I have a 1989 Corolla and had the alternator fail/seize/die on me. The alternator still worked but only charged to around 11volts (was replaced some time ago dont remember the exact reading). Made it hard to crank the engine over ect.

Anyway if your daughter has the 4AFC carby engine, then replacing the alternator is a pretty straight forward jobs. Think there was 2 bolts, one to hold it in place on the mount and one to adjust the tension. It now charges to 14V. I paid $50 including postage for the alternator.

[Blind Kid Seeks]

Failing Brushes is not an uncommon thing in 4A series Alternators...

I had a similar problem.. although my Check light was working....

Autoelec i took it too tried to sting me for a new Alternator... without even looking at it... but i insisted that it just needed new Brushes and the bearing inspected... which they did... and it was 100% sorted afterwards... good result... the 4AGE alternators are different apparently compared to the 4AFC ones. massive price Difference too.

[Rolla Boy]

Thats because the FE alternator is a Bosch type and the GE is a Denso...

Bosch have a voltage reg that can easily be replaced...

Denso don't, the regulator is internal...

[supertownace]

irrespective of the make/type of alternator they are all simple in design and therefore easy to repair/rebuild. i used to have a small time business repairing/rebuilding oddball alternators and starters that no one else would touch. costs were for parts plus $50. most times it worked out on average at around $70 to $80.

if you are handy with simple hand tools, a bench vice, and a soldering iron you can repair an alternator at home. and most parts are available from any good auto leccky shop

cheers

[Peal]

irrespective of the make/type of alternator they are all simple in design and therefore easy to repair/rebuild. i used to have a small time business repairing/rebuilding oddball alternators and starters that no one else would touch. costs were for parts plus $50. most times it worked out on average at around $70 to $80.

if you are handy with simple hand tools, a bench vice, and a soldering iron you can repair an alternator at home. and most parts are available from any good auto leccky shop

cheers

I took the alternator down to an auto electrican this morning. They checked it on their test rig, & confirmed it was the regulator. They had a refurbished Bosch identical model to mine for $165. Put iy in & all OK now. Dash light now works as well.