generator warning light - alternater conversion

[lard]

Daft question time - if I've had an alternator conversion - should the green generator lamp still work on the dash with ignition switched on? Mine doesn't, changed bulb and can only see two connections on the alternator, one heavy wire that goes to the battery and blue wire that I assume goes somewhere....

Cheers!

Larry

 

[lard]

o.k. - checking wiring diagrams and it goes straight from the bulb to the regulator so will hunt this down in the engine bay - I have noted a wire with a particularly poor looking connection that may explain it, assuming the regulator is behind the fuel tank cover on a 71...?

 

[lard]

Done some initial looking - seems with my alternator I have a built in regulator - pull the blue wire off and ground it = light on dash which is good,

Going to confirm it's connected to the correct terminal - currently on the middle one, could be a case of it not being attached to correct pin!

 

[67panel]

warning light wire from old dynamo reg should be conected to spade on alternator,i normaly connect old field wire to warning light terminal on alt,then join old field wire to light wire at old control box conections ,saves using new cable and is tidyer as loomed up.same with main feed .do you have two terminal alt or is there block of 3 terminals,if so you need external reg

 

[lard]

warning light wire from old dynamo reg should be conected to spade on alternator,i normaly connect old field wire to warning light terminal on alt,then join old field wire to light wire at old control box conections ,saves using new cable and is tidyer as loomed up.same with main feed .do you have two terminal alt or is there block of 3 terminals,if so you need external reg

Hi - I have the 3 spades in a U shape - d, df & d+

All seems to be working at the moment (though going to get the voltmeter and confirm charging is working when running!).....and can't see a regulator or voltage stabiliser in the engine bay - the blue spade connector is currently going from the loom straight onto D+ with a thick red from the bolt down to the starter motor

Does sound like I should have an external regulator fitted then with the 3 spade alternator??

EDIT: Just pulled air cleaner and B+ goes straight to battery - can't see a regulator in the engine bay - going to whack the voltmeter on whilst running to see what voltage is getting pushed back into the battery - I'm assuming if it is high (15+ volts) then this proves the lack of internal alternator regulator!

 

[Araon]

http://www.vw-resource.com/alternator_wiring.html" onclick="window.open(this.href);return false;

 

[lard]

Cheers - had a good look through that and I *think* it's becoming clearer:

Looks like I have an alternator that's supposed to have an external regulator - but it's wired for an internal regulator version :?

Run up the engine - place voltmeter onto the B+ post going to battery and other end to ground:

No rise in Volts when running up RPM of engine = no output from alternator (is it safe to disconnect the battery completely from the alternator to confirm as much? I'm assuming not as it could burn out the windings)

Also tested RPM using tacho of voltmeter.....showing no RPM when engine running - I believe it calculates the RPM from the pulsing of the alternator and this would again indicate that the alternator is fried

Haven't really done any miles or had the van long enough to work out if the battery isn't charging - I've had to put it on charge once after I got it in the garage, it's showing 12.55V standing, this drops to 11.98V when van running (no matter what the RPM of the engine)

From the above am I safe to assume the alt is knackered? Any more tests I can do?

If so I'll get an internal regulator one and that should sort it...!

Thanks,

Larry

EDIT: Having a blonde moment - there's no regulator connected - tested output from the spade connectors as I assume the regulator needs connecting before B+ will output...it sits at 7V on idle and increases with RPM so think the alternator is good - though at £35 for a regulator there's more value in a new alternator for £100

 

[lard]

Well - I took the plunge and shelled out for a new internal regulator alternator from VWHeritage - JK wanted a surcharge on the old unit and I didn't have one

What a mare of a job! - that 36mm fan nut on the rear is a bitch indeed, had to go out and get a bigger breaker bar :shock:

Managed to trash the old alternator as I had to jam the rotor due to the amount of force required to release the fan nut and I risked damaging the pulley using a screwdriver to wedge it - but hey ho, got there in the end and completed my first proper job on an aircooled engine :mrgreen:

So all back in, turned on the ignition and generator light comes on! - fire up the bus and it goes out 8) - just chuffed that my guess was correct after all that - need to take it out for a run but happy that it's back together again (hate having to leave a job halfway through as I think I'll forget how it goes back together!)

Tip for anyone changing alternator/dynamo - having a 10mm ratchet spanner for the lower 2 bolts on the alternator fan plate saves a load of effort and having to raise the shroud so high- didn't have it dismantling and it saved a lot of swearing when putting back together

EDIT:

My brother also made me feel like an idiot - you're supposed to put the voltmeter probes on the coil and earth rather than over the battery to get RPM to display as it uses coil pulsing to detect RPM - oh well, lesson learnt! (RTFM :lol: )