Battery Light

[JTremendous]

Hey guys !

So I took my 83 944 to the drag strip yesterday and after I got done racing I noticed that when I turn the key to the acc position that the battery / alt light does not come on. This light has always worked and this would not bother me except that I have read that the alt will not charge the battery if the light is not working, however I drove the car all night last night and it didn't seem any different and even this morning the battery is still going strong.

What do you guys think might have happened and do you think it is ok for me to keep driving it? Thanks

[bearone2]

you're correct about the light being part of the charging system.

check voltage when it's running, should be upper 13's to low 14's with lights, fans on at operating temp.

[JTremendous]

Yea I am only getting 11 volts, I believe the alt to be good and something either wrong with the light itself or a loose connection or ground, any Ideas?

[bearone2]

pull the cluster and change the bulb.

[JTremendous]

I pulled the gauge cluster, i am going to replace all the bulbs, what kind of bulbs to i need for both the cluster and the battery bulb because it is bigger, also when I pulled the cluster i found this wire unplugged, do you guys know what it goes to and where it plugs in at.

[bearone2]

when my lite didn't come on in the '84/944, i removed and went to napa.
i don't recall it being bigger than the others.

not sure.

was there an empty hole in the cluster?
if you have a haynes manual go by color coding in/around cluster.

[JTremendous]

Yea there are acutally three size bulbs, one for the back light for the tach and speeometer, one size for the warning lights like oil and low fuel and then a big one for the battery warning light, I changed the light for the battery warning and still get nothing.

[JTremendous]

here is the big battery light and the other pic shows all three size lights one for the speedo to the right one small size on the gauge cluster to the left and the big one is the battery light, ignore the open hold on the gauge to the left i took the temp light out to change.

[bearone2]

did you replace with a known good bulb that had a good continuity check? if yes, the alternator/vr or wiring is bad.

you're lucky you got home with all the driving.

[JTremendous]

yea i drove for probably 20 miles last night with all my lights on and did not notice anything, where is the voltage regulator at for our cars

[JTremendous]

This is a weird problem becuase most of the time with alt problems the light stays on as most people with battery light problems have posted, but mine doesnt even come on which makes me wonder if it could be the vr or alt at all, all the other lights work like the low oil, turn signals, and high beam light

[bearone2]

it's supposed to come on when the key is turned on and go out when the engine starts and the alternator is 1/2 a volt above batt voltage.

if you have an alt failure, the light comes on to tell you.

on the later models the light wasn't a factor, early yes and on several different vehicles with bosch electical systems. think of it as xmas lights in series, one goes out, they all go out.

i had the same problem 30 years ago on a volvo with a bad bulb.
i popped the hi-beam bulb out(no instrument removal), put in the alternator light socket and circuit completed, voltage was up where it needed to be.
i replaced the bulb for the hi-beams.

i was told the light bulb as part of the charging system configuration was one of the goofiest things bosch had done by a volvo service tech.

[JTremendous]

Bearone2 thanks for your help, I know what the problem is... finally

The brushes on the voltage regulator wore down so much when i was racing last night that it no longer contacts the slip ring and therefore didn't ground out the blue wire which resulted in a no battery light situation, I took the blue wire off the alternator and grounded it to the battery - cable, and then with the key in the acc position the battery light came on full blast, and it shines brightly with that new bulb I put in earlier today. Sometime this week I will go and buy and new voltage regulator. =)

[bearone2]

i hadn't mentioned the blue wire, sorry. that's what i was thinking of when i said wiring, maybe it had fallen off, etc.

vr's aren't too expensive and you should be able to do it on the car. good luck.