Technical Generator Light on, battery not charging

[DimitriL]

Hi everyone, I've read all the posts on this subject and the stickie manual on this issue. My Generator light stays on while I drive and even sometimes when the key is out!
- With engine running, I measure 1V at the field coil connector and 1V at the power coil
- I tried bridging both connectors on the generator and measured, same thing 1V.
- I tried 'flashing' the field coil with 12V, I did get the spark, but same issue.
- I opened up the Original Fiat regulator and noticed that the third solenoid is closed and when I lift plate, the Generator light on the dash goes off and when I start the car, I have battery voltage (now low, since it isn't charging anymore) so I have 12.3V on the field coil and about the same on the power coil.
But when I closed the generator cover, and started the car again, the generator light was on again and again only 1V over each connector at the generator.

My reasoning now:
It seems that the generator works, as when it gets 12V on the field coil it gives me 12V on the power coil (however, when I revved, voltage stayed the same...) so could it indeed be the generator??
Or I would believe that the regulator is not good?
Relay 1 & 2 are open and Relay 3 closed. Is that how it supposed to be?
Is there a way to test the regulator? I placed the car now on a trickle charger.
Any help would be appreciated, thank you!

 

[Vitesse]

Hi everyone, I've read all the posts on this subject and the stickie manual on this issue. My Generator light stays on while I drive and even sometimes when the key is out!
- With engine running, I measure 1V at the field coil connector and 1V at the power coil
- I tried bridging both connectors on the generator and measured, same thing 1V.
- I tried 'flashing' the field coil with 12V, I did get the spark, but same issue.
- I opened up the Original Fiat regulator and noticed that the third solenoid is closed and when I lift plate, the Generator light on the dash goes off and when I start the car, I have battery voltage (now low, since it isn't charging anymore) so I have 12.3V on the field coil and about the same on the power coil.
But when I closed the generator cover, and started the car again, the generator light was on again and again only 1V over each connector at the generator.

My reasoning now:
It seems that the generator works, as when it gets 12V on the field coil it gives me 12V on the power coil (however, when I revved, voltage stayed the same...) so could it indeed be the generator??
Or I would believe that the regulator is not good?
Relay 1 & 2 are open and Relay 3 closed. Is that how it supposed to be?
Is there a way to test the regulator? I placed the car now on a trickle charger.
Any help would be appreciated, thank you!

Hi relay 3 is the cutout relay. 1 is the voltage regulator, 2 is the current regulator. With the engine not running all 3 should be open. Only when the generator reaches a high enough speed will the cutout relay energise and allow a flow of current to the battery. The voltage and current relays will open and close to regulate the flow and keep it at correct levels. If the cutout relay is closed it will allow a path for the battery to discharge via the generator to earth. Which is also why your generator light stays on with the key out because it has a path to earth because the cutout relay contacts are closed, hence when you opened it, it went out.

It’s highly likely that the Voltage Regulator is faulty. I have seen the cutout relays windings burnt out or contacts welded together before. Even in your picture, I am not 100% sure but on the backing plate it does look there might be signs of it getting a bit hot in there?

You can get an electronic VR replacement which is likely to be more reliable and cheaper than the mechanical ones.

Tony

 

[DimitriL]

Hi and thank you for your input! The engine compartment does get hot, yes.
It's interesting that the 3rd coil keeps closing even when the engine isn't running (so it cannot be that the coil get's energized, so it must be a spring forcing it closed I think. I am just trying to find a way and hope that I could take it apart and somehow fix it. I was watching a Youtube video of a guy fixing same looking regulator of a tractor, he said 80% of the time it's the points that need to be cleaned. I am definitely going to look into an electronic one.

 

[DimitriL]

In the mean time, I just ordered an electronic regulator off Ebay. Maybe with the electronic one, never problems again.

 

[lazylobster]

I had too high a voltage hitting my battery and cooking it. I swapped out to an electronic reg and no issues. Your mechanical regulator is probably as old as the car. So it's done a lot of years service in a hot environment.


I have an original Fiat service manual. The procedure for setting up the mechanical reg is quite involved! Bin it, fit the new electronic one and hopefully, job done!

In fact, just taken a look at the manual, for example, for one of the settings, you have to have the reg in an enviroment of 50c, so they have it shown in a little oven with a remote prong to make the setting. I'll take some pictures and post it here for ref.


R

 

[lazylobster]

Workshop manual pictures. Hopefully of some use?

 

[DimitriL]

Thanks so much! That manual that you have is precious! So detailed! If I saw this earlier I would have dared to play with it a bit. But anyway, let's see what the electronic regulator will do. I hope all is okay with the generator (I believe so). This service manual that you have, I don't believe anyone has ever uploaded scans of it here on this site? If not, I'm sure not only me would like to have it, in case I need to figure things out. Hint...Hint... Wouldn't mind to pay. Cheers!

 

[F123C]

Hi Dmitri?,

If you click on the Downloads section, located in the blue band at the top of the page, then scroll down and click on 500 (Classic), you can download (for free ) a copy of the official Fiat Workshop Manual which has lots of info on the Generator, pages 112-114 and the Control Box (i.e. the Regulator), pages 116-118, which includes the checking and set-up procedures (although not as comprehensively as in the manual pages that Lazylobster has kindly posted ). You can also download a copy of the Owner's Handbook if you wish.

Hth,

Al.

 

[lazylobster]

Hey and es I will get around to scanning the manual at some stage in the future. It's very comprehensive and no, won't need any payment for it. But thanks for the offer.


As you can see from the pic, the Haynes manual is 167 pages, the Fiat manual is 400. So quite a task. But the detail is amazing. Think I got it off the Bay of E, a rare find especially in English.

Cheers
Rob