Red warning light, what is it?

[haraldkl]

Hi, today a red warningligt started glowing. The picture showes the instrument with 2 lights, one green at the top, and the red one at the bottom. Both lights are bright when key is in and engine is not yet started, after starting the green light goes off, but the red one stayes on, but not so bright shining anymore.

It seems that the battery is loosing power, so this might be some warninglight to tell that the battery is not getting charged. Does anyone know?

Sorry about the quality of the picture, it was taken with my phone and its getting a little darker around here now.

If this indeed is a warning for to low or missing charging, what would be the most likely thing to check first? I am now a 3 day old porsche-owner, so this is making me a little nervous.

:-)

---kenneth---

[HawgRyder]

Looks like the Altenator light to me.
The problem is...that is the same light that would indicate undercooling or broken cooling belt!!!
Better check it very quickly.
Bob

[haraldkl]

Thanks, on my way to check now!

--kenneth---

[ossiblue]

Kenneth,

HawgRyder has you going in the right direction, and you were right, it is the light indicating low charging--especially since your battery is losing charge. First step is to check all connections and grounds--at the battery, starter motor, ground straps by battery and trans. Check the easy things first. Check condition of battery too. Monitor voltage to battery with engine running. When in doubt, find a reliable mechanic to check the output of the alternator and voltage regulator (most likely "part of" the alternator). Electrical can be a PITA, but what you describe is not uncommon.

Good luck.
Larry

[haraldkl]

Well, its not the cooling belt. What does the Altenator light tell me then? DOes it say "low charging" or "completely missing charging"?

The engine temp climbs to around 180 when im driving, and I'm told that that is a normal temp for the car. So it doesn't seem to be any cooling problem.

I will check the battery and the other connections, thanks for answering.

---kenneth---

[cak]

You don't say what year/model you've got, so we don't know if you have an "internal" or "external" voltage regulator.

That said ... I just went through this here.

There are also a lot of older threads that I found helpful, search for "voltage regulator"; here are a couple:

Need to test and rebuild alternator

Testing a voltage regulator

Good luck.

[JP911]

It is the alternator warning light. If it stays on when the car is running then you either have a charging problem or the light has decided to stay on for some reason (the latter is unlikely). Step one is to put a multimeter across the battery with the car running to find out what the alternator is doing to the battery. It should be somewhere between 13-14 volts. If it is below 13 or above 14, then something is wrong with the charging system. I would avoid driving the car until you get this sorted (lest you get stranded or have a battey overcharge and melt down).

[Gogar]

Also, on the older cars, the light may appear to glow faintly, especially at night, but it's perfectly normal.
Follow the other good advice in the thread, and you'll figure it out. If the light gets dimmer, but doesn't completely go out, I'd suggest your problem is a smaller one, but still a problem. Again, What year of car?

[lonewolf]

batts not charging,
bright glow alt , reg problem
faint glow can be bad ground.

[haraldkl]

Its a 1976 911S US, battery is now not holding enough current to start the car.

---kenneth---

[haraldkl]

Anyone have a picture of te Alternator or the regulator so I know what to lok for?

:-)

--kenneth---

[lonewolf]

alt is behind fan
reg is inside the reg panel on left side on eng comp . reg panel amy or may not have plastic cover . reg is beside ign cd

[haraldkl]

This is what hapen next: I put on a battery-charger, it sits there for 2 hours, and when i start up the engine, the light is gone. Could it really be the battery after all?

---kenneth---

[Patton]

Have you checked the battery voltage with the car running yet?

[lonewolf]

check with voltmeter at batt when car is running to see if you have 13.5-14.0 or 14.0-14.5
see what you have at idle. then rev eng, numbers should go up.
then at idle turn on some accesories, headlights high beam, fan ,ect , voltmeter will drop a little, then rev engine if numbers go up alt and reg are fine but they have to go up to at least 13.8-14 ,even better 14.0-14.5 otherwise you have low output.
grounds are very important in a porsche ,check to make sure all your grounds are good. the grounds for alt and reg are attached to the panel on left side of eng compartment but that panel has a ground strap on the top right corner and attached to a ground stud behind fuel accumulator. thats a very important ground.

[Joe Bob]

12.5 volts at rest
13.0 at idle
13.5-14 volts at 2500 rpms

Tested at the battery terminals.

[lonewolf]

sorry mike i respectfully dissagree
the reg is designed to allow 13.5-14.5 into the system
start eng and slowly rev to 3000-3500 , voltage should not very much more that .05 volts .you should have a minumum of 13.5 and that might not be enough depending on condition of your charging system. better to see 14.0. the system runs better at 14-14.5 then at 13.0-13.5 difference is small but means the difference between a fully charged batt and one thats barely hanging on