Help (I'm an Idiot) -- 308 Gauges Dead and Battery Light is on when key is out...

First thought, check fuses and relays. Do you have birdmans fusebox?

 

Look at the wiring diagram in the manual and see what relay/fuse powers that light. Then check other items it powers and if they are on or problemed.

 

That light usually means the alternator is not working. You may have blown a diode in the alternator regulator. Make sure that the alternator is charging. If your gauges are working again, you should be able to tell if the system is charging or discharging when the engine is running. If discharging, you probably blew the regulator. Just a thought. You can also check with a multi-meter and measure voltage across the battery terminals.

 

Yea, you fried the alternator!

 

I think I recall a thread a while back on alternators. Isn't there a substitute alternator that you can get at the local Napa Store? Joe

 

rebuilds on these are fairly straight fwd,. and not very expensive.

 

Couple of points which requires a basic understanding between electric and electronic parts.

Electric parts are lights, relays, motors, pumps, switches, and most sensors. They can have polaritity reversed without incurring damage.

Electronic parts have semiconductors and include such devices as radio, regulator, ignition modules, ecu modules, gauge transducers. These will incur catastrophic damage if voltage polarity is reversed. HOWEVER they are often diode protected from this by the manufacturer against this eventuality. ...but one never knows.

When an electronic part has failed due to polarity reversal, it can either fail open or shorted. Alternator regulators will failed when reversed and there is enough power available for them to blow wide open. The alternator itself is electric and not in danger.

One you are back to running you will need to checkout all gauges, fuel injection modules, slowdown circuits, and cat temp modules. I enumerate the two categories of parts so you don't waste time fretting over electrical parts which are not subject to failure.

 

I hooked a battery backward to my 308GTB when jumping a dead one in the car....rebuilding the alternator fixed it.

Good luck!

 

Once upon a time, there was a handsome good samaritan who encounters the fair maiden with a dead battery. He pulls out his
jumper cables, parallels cables between the two vehicles and promptly blows out his near new alternator is his near new truck
because he wasted time chatting her up instead of paying attention to black and red.

That story is now repeated by their kids. If it was their grand kids it would have been a 6volt generator, not an 12volt alternator,
and it would have survived as voltages regulators in those days were simply a pair of relays. And since in those days radios
drew lots of power requiring restarting parted cars every 30 minutes to keep the radio going and studs were well versed in the
vagarities of maintaining a reliable batterie.

And 20 years before then one simply started the car with a crank. I ask...when was the last time you even SAW a crank.
Or saw a car with the hole in the radiator to allow the crank to the crankshaft pulley. So which side of the Ferrari would
Enzo have plaed the crank, were he 50 years earlier? Ahh gotta start a poll.

 

I cannot remember writing this, but find it quit amusing and while so, am beginning to worry ... how do you spell oldtimer's?

 

Paul you should also mention how to jump start a positive ground 12V system. My 1st car was one so I'm an old timer. By the way I never hooked one up backwards yet but there is still time left.

 

There are two Model Ts in my Dad's garage. A Truck and a Coupe.

And YES, although they have starters we ..... use the CRANK.



[The novelty NEVER wears off.]


The first time either backfires and runs backward thou (YES, they can), will probably be the end of that.