1975 battery Indicator light stays on, any ideas why?

[Betis]

When I start the car, the battery indicator stays on, instead of turning off after a couple of seconds. Any ideas why? As far as I know the battery is ok. What else could be wrong? What should I check.
Thanks

[azruss]

sounds like your alternator is not charging the battery. don't know if the 75 still used the external regulator. ( big box on driver side inner fender). If it does, then one of the contact in the regulator is welded shut. Best test is to start the car and put a volt meter across the battery. should be reading in the 13.5 volt range.

[toplessexpat]

Weirdly - my alternator light has been cheerfully glowing for the last 18 months. Battery charges just fine. It's not on all the way - just noticeably glowing so I've put it down to (likely) a dodgy earth behind the dash. At some point I'll take a look - but for now I'm somewhat used to it!

[bradartigue]

Common conditions:

- bad ground (80% of the time)
- bad voltage regulator (15% of the time)
- bad alternator (5% of the time)

Many times alternators are replaced when the VR is bad; test it, replace if faulty.

[kilrwail]

Let's not forget to check that the belt isn't broken! Before we overheat! LOL

[Betis]

Today I was driving and the light went out. But then when I started the car again awhile later and the light came on again. Any ideas why?
Thanks in advance.

[rridge]

On a '75 Spider the alternator light is turned on and off by a relay on the driver's inner fender. Sometimes the relay stops working. Sometimes the connections at the relay or on the back of the alternator need cleaning. Locating the relay in an engine compartment full of them is the challenge. Brad Artique has posted a series of Fiat service letters from the 70's and early 80's. One of them contains a diagram of relay locations for each model and year.
You can find it here:http://www.artigue.com/wp-content/uploa ... /000-6.pdf

Richard