alternator problems

[richlowndes]

I had an alternator conversion last year and all has been fine till now...

The generator light in the dash is on when the engine's running, and the alternator is not charging the battery. I can get it to start charging by shorting out the two terminals on the alternator. It will then charge until the engine is switched off.

The +ve feed from the dash is working fine and there are no short circuits between the generator light and the alternator (I have replaced the wire to be sure and it makes no difference).

When the engine is off but the key is turned to the on position, (without starting the engine) the generator light should be on, but it flickers between on and off constantly and sometimes doesn't come on at all.

Any ideas? I'm reluctant to fork out for a new alternator.

Thanks
Richard

 

[Clarkson46]

As a simple check, disconnect the blue wire from the alternator and earth it somewhere, now switch the ignition on. Does the gen light still go on and off? If so, then you have a problem with the wiring to the gen light. The gen light is used to provide a 12 volt source to "energise" the alternator, so if your gen light fails for any reason the alternator will stop charging. From the description it may be the regulator that is at fault which, depending on the alternator can be replaced separately.

 

[58herbie]

Richard,

if you take the blue wire off and touch on the earth wire or to the case of the alternator the gen light should come on constant and stay on ( just with ign on, not engine running).... if you take the blue wire and put to the red wire it should put the light out..(thus making the van think it is chraging).. if this happens i am affraid to say you have an alternator problem.. i think a diode hhas gone done this is whats giving the flikering you are seeing.. you generally have 3 sets inside a set has probably failed..

jon