Alternator no dc but 26volts ac out.

[Tony54]

Hi all, 

First post so sorry for not saying hello for newbies but will do so after posting this. My  car is a t22 avensis 2002 1.8vvti auto and the alternator has stopped working. The only voltage out is 26v ac., I have checked all the fuses and continuity and all ok and i have a fixed 12v and another 12v to the alt when the ign is on. I just wondered if any experts could advise me what could be wrong. I assume it might be the regulator which i believe is built into  the  alternator. If it is the regulater does anyone know where to buy these and also new brushes in case they are past their best. Thanks Tony.

[Mark O]

With the alternator running, check the voltage across the Battery terminals. Obviously set meter to DC and range for 12V. It should rise when revved. It should not remain static.

Yes, it could be the regulator, more correctly the regulator/rectifier ( reg/rec), or the brushes  - but unsure just how easy it would be to replace these items or what the cost is. If cheap and easy, go for it. Mr Toyota himself for parts, Fleabay and loads of parts places on the web.   

Failing that, and if it could be established that the alternator is at fault, I would simply purchase/install a tested second hand alternator. Should not be that pricey...

[TomdeGuerre]

31 minutes ago, Mark O said:

Yes, it could be the regulator, more correctly the regulator/rectifier ( reg/rec), or the brushes  - but unsure just how easy it would be to replace these items

I'd sure be interested to know how the brushes could cause 26 VAC output on the alternator.

[Mark O]

Of course, worn brushes will not cause 26V AC and that is not what I was alluding to. I was referring to the previous sentence which refers to the static voltage across the Battery terminals.   

[Tony54]

Hi guys, sorry for late reply. I.m getting a fleebay replacement tomor hopefully. Hope it solves the problem. Once im on the road again i will strip the alternator down and let you jnow what the problem was. Thanks. 

Tony

 

[IanML]

On 10/8/2016 at 4:42 PM, TomdeGuerre said:

I'd sure be interested to know how the brushes could cause 26 VAC output on the alternator.

Not brushes. Diode broken down and short-circuiting?