jss

I don't understand. with my other cars I usually get a new voltage reg and it fixes problem. but on with the 944 it didn't work. I also tried a spare alternator I had at home and still same ****.

is there something I am overlooking?

FabilichuS

Maybe the altinator belt is not tight ?

jss

its tight

xsboost90

bad connection up by the brake booster?

Mighty Shilling

Bad connection at the starter? have that off for any reason lately? with my 924, I left that loose.... wouldn't charge the battery.

JohnKoaWood

Bad / Corroded cables may also be at fault...

jonvo

What year is your car? In the early models, the alternator exciter wire goes through the alternator bulb in the dash, and if the bulb is out, it will cause this problem. Try turning your key to the on position and see if the warning light on the volt gauge lights up. If it doesn't your problem should be solved by replacing it.

jonvo

I completely missed the part of the title that said you need to rev past 2500 to make the light go out. Sorry! Maybe there is a broken wire or connection in the exciter circuit?

m73m95

Voltage regulator is going out. Mine did the same thing, for about a week. Then it wouldn't charge at all. Time for the the VAN rebuild thread!

They can be rebuilt for cheap.

jss

I did replace the exciter wire and added 4 gauge new wire from alt to starter. so that is great.
i think I may have a problem with the wire from the batt to starter.
i think its a 2 gauge wire?

DarylJ

Your alarm is disconnected or broken, right?

Early944

My voltage regulator went out last week. Didn't seem to be rev Dependant though when it was dying. I drove it out to the end to

jss

factory alarm removed

DarylJ

That's the problem. The D+ (field) current goes through the factory alarm. If you disconnect that, you never get 12v to the alternator to start the field current and make it work, and have to rev it up far enough to auto excite (the better shape the alternator is in, the lower this number will be).

You need to get keyed power to D+ (the blue wire) to solve that. I dug through the electrical diagrams a few years ago when someone else was having this problem and found what pins on the old alarm harness you need to bridge to fix it.

Here's the post, with diagrams.

jss

ooooooooooooooooooooooooooo good call I was losing my mind here. I spend last night redoing all wiring in 1gauge and still does the same thing. mind u my volts is higher then b4 which is good...

just so I understand I need to bridge 8+7 to make the alt light go out.which is located under glove box