Technical Why does the red light on the dashboard with a “g” on it stay on when the engine warms up ?

[Simon1234]

Hi All

So, new problem
I have recently overhauled the electric main wear parts on my Classic Fiat 500 L 1970 car. It run the 126 engine.
Replaced: Dynamo, coli voltage regulator and replaced the distributor with 123 electronic ignition. All works well.
Previously, the red “g” light came on on startup, flickered on tickover and disappeared when running.
Now, comes on on startup, flickers on tickover and goes out when running at first. Then reappears when the car has traveled about 5 miles staying on.
I stopped and checked oil levels all fine. So, continued my journey no noticeable difference with engine running in any way.

I have checked the wires to the oil pressure sensor all good, so I’m going to replace this tomorrow.
Any advise out there ?

 

[Simon1234]

So, revising my concerns and having found the Haynes manual on both the 500 and the 126 not helpful in this area. I reviewed the owner handbook. Of course to discover that I looking at the Ignition Warning Light not the oil light.
To assist anyone else I’ve added a copy of the relevant page

Same question re this light

 

[fiat500]

Simon, you either have a loose or damaged fanbelt, worn brushes or other fault inside the generator, loose or damaged wire/s or connection/s or possibly a faulty control-box.
Before going in deep, I would check the belt and all connections. I had this problem last year and it was dirt and wear inside the ignition switch.

 

[Simon1234]

Simon, you either have a loose or damaged fanbelt, worn brushes or other fault inside the generator, loose or damaged wire/s or connection/s or possibly a faulty control-box.
Before going in deep, I would check the belt and all connections. I had this problem last year and it was dirt and wear inside the ignition switch.

Hi Peter
Thanks for your reply

I replaced the belt when I fitted the new Dynamo last week, and I replaced the voltage regulator, coil and distributor

Poking about with a tester (why on earth those things are not magnetic for ease of use I have no idea - who has three hands ?) looking for output there is no output from the dynamo, presumably hence the light on.
Now I painted the retaining strap while it was off during my continuous engine bay tidy up, could I have killed the earth ? Does it require an earth ?

Ive checked the connections and they are all good it must be something basic that I’ve disturbed missed or caused.

When I fitted the new 123 distributor all was well for about 5 miles. No warning light. But, now it’s on from the get go.

I am very fortunate as there is an old style garage called Autobritalia close by run by a couple of great genuine guys ( one of which runs a classic 500 ), Who ran me through the wiring but, after about 30 seconds of B+ s B and other terms I was lost. They are v busy until Monday but the thing is I could give it to them but I wanted the challenge and the reward. And I’m enjoying the car enormously ( the last thing I restored was a 1946 MKVI Bentley Special - so I also enjoying the much smaller costs ).

Ironically, the car is running brilliantly, smoother than ever. So, you can imagine all I want to do is drive her !!

simon

ps. I have limited skills but loads of enthusiasm

 

[fiat500]

Hi Peter
Thanks for your reply

I replaced the belt when I fitted the new Dynamo last week, and I replaced the voltage regulator, coil and distributor

Poking about with a tester (why on earth those things are not magnetic for ease of use I have no idea - who has three hands ?) looking for output there is no output from the dynamo, presumably hence the light on.
Now I painted the retaining strap while it was off during my continuous engine bay tidy up, could I have killed the earth ? Does it require an earth ?

Ive checked the connections and they are all good it must be something basic that I’ve disturbed missed or caused.

When I fitted the new 123 distributor all was well for about 5 miles. No warning light. But, now it’s on from the get go.

I am very fortunate as there is an old style garage called Autobritalia close by run by a couple of great genuine guys ( one of which runs a classic 500 ), Who ran me through the wiring but, after about 30 seconds of B+ s B and other terms I was lost. They are v busy until Monday but the thing is I could give it to them but I wanted the challenge and the reward. And I’m enjoying the car enormously ( the last thing I restored was a 1946 MKVI Bentley Special - so I also enjoying the much smaller costs ).

Ironically, the car is running brilliantly, smoother than ever. So, you can imagine all I want to do is drive her !!

simon

ps. I have limited skills but loads of enthusiasm

Simon...the dynamo does need a good grounding to the engine and the engine to the body. The body of the dynamo is usually unpainted under the securing band. While looking at it, do you still have an earthing strap from dynamo to the rear panel? You're lucky having experts nearby and I like the sound of your enthusiasm.

 

[Simon1234]

,

 

[Simon1234]

After much testing from the battery to the dynamo. Breaking the starter cable in the process, electrocuting myself a few times

and mucking about it would seem my new dynamo is faulty.
Sods Law, so, today my mission is to take it out and tomorrow send it back.
I have enlisted my 9 yr old grandson to assist me, should be fun

I will get this Bambino running !!!!!

 

[Simon1234]

My grandson helping me - he had no idea what to do with a spanner
Whatever happened to Meccano ?

He does now

Dynamo removed ready for the second replacement

 

[Simon1234]

update - the dynamo has been sent back to Ricambio for a warrantee inspection, I await the outcome , hopefully quick. And I went on eBay and bought my grandson some Meccano ! Well I can only plant the seed

 

[plasticpig1972]

update - the dynamo has been sent back to Ricambio for a warrantee inspection, I await the outcome , hopefully quick. And I went on eBay and bought my grandson some Meccano ! Well I can only plant the seed

Hi Simon,
nice thinking with your grandson lol
Alan

 

[Simon1234]

So after much hassle and a few scraped knuckles the replacement dynamo is in.

A technical note: be careful that you don’t put the spacer on the cooling fan side of the dynamo back the wrong way round. The fan will move freely right up to the last turn of the bolt them it won’t. That’s the tell. Probably a rookie note but there it is.

Anyway, the new dynamo works No Red Light so, despite Ricambio never having a faulty refurbished dynamo before they have one now!
Although they have been very helpful indeed, it happens to the best of us.

Job done, took the Bambino out for our first full fun run without breaking down in 10 mins.
I wonder what will be next ……………