 Alternator Light ON most of the time, How do I determine what's wrong? |
|
|
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
|
| ThinAir |
 Sep 25 2007, 11:48 PM
Post
#1
|
|
Best friends  Group: Members Posts: 2,564 Joined: 4-February 03 From: Flagstaff, AZ Member No.: 231 Region Association: Southwest Region 
 |
I HATE electrical problems!!!! Okay, with that out of the way... here's the deal.
My car went 800 miles round trip for Red Rock Classic with no problems at all. When I shut the engine off in the driveway I had no glowing alternator light. A couple of hours later I start it up to move the car and the alternator light is on. I ran the car some to try and determine if it was really on or just glowing and discovered that the light went out and seemed to be tied to the engine rpms. Well I've tried to tighten the belt, but have gotten no different results. Most of the time when I drive the voltmeter is sitting just under 12 volts and the light is glowing dimly, but if I am idling the light is on strong. Once in awhile the light will go out and the voltmeter will show 14 volts, but there is no consistency to it. The AA Tech Tips book says this: Condition: Light off with key off Light on with key on Light glows dimly when car is running Problem: Bad diode in alternator or bad ground Since tightening the belt has not made a difference, it seems like it must be one of these things. The question is how do I tell what it is? Since the car starts consistently I know that the tranny ground strap is well connected and that's been confirmed. Since the alternator grounds to the engine case, where else could there be a bad ground? |
   |
 
|
  |
Replies
| ThinAir |
Sep 29 2007, 02:27 PM
Post
#2
|
|
Best friends Group: Members Posts: 2,564 Joined: 4-February 03 From: Flagstaff, AZ Member No.: 231 Region Association: Southwest Region
|
So... along the way I found this topic by Brad Anders in which he states that his alternator had a bad ground. Since this is one of the possible causes cited by AA in the 700 tips book, I'm wondering what this is. The alternator is grounded to the engine, which is grounded through the tranny ground strap - if this is all connected properly, what else is there?
BTW the Richard Atwell page that Brad references is an incredible resource. I'd forgotten about his site. |
|
|
|
| Gint |
Oct 7 2007, 10:45 AM
Post
#3
|
|
Mike Ginter Group: Admin Posts: 16,096 Joined: 26-December 02 From: Denver CO. Member No.: 20 Region Association: Rocky Mountains  |
QUOTE(ThinAir @ Sep 29 2007, 01:27 PM)  BTW the Richard Atwell page that Brad references is an incredible resource. I'd forgotten about his site. I fixed your link Ernie. |
|
|
|
Posts in this topic
ThinAir Alternator Light ON most of the time Sep 25 2007, 11:48 PM
Rand Just because it's so easy... Check the contact... Sep 25 2007, 11:58 PM purple check fuse #9. you may have inadvertently kicked i... Sep 26 2007, 08:17 AM ThinAir Well I've checked fuse #9. It's good and ... Sep 27 2007, 08:47 PM SirAndy check the contacts on the alternator harness first... Sep 27 2007, 09:03 PM ThinAir Clean contacts for the alternator wiring harness d... Sep 29 2007, 01:34 PM Headrage I'm not sure how accurate it is but you can ru... Sep 29 2007, 01:48 PM ThinAir Duh - I just called my FLAPS and they say they can... Sep 29 2007, 02:09 PM
ThinAir
I fixed your link Ernie.
Thanks, Mike. Obviousl... Oct 8 2007, 02:06 AM ThinAir Replaced the alternator today. What a pain, but i... Oct 6 2007, 11:51 PM ejm
The problem here is corrosion. Many of the mecha... Oct 7 2007, 06:11 AM BMartin914 Ther alternator also grounds through the brushes. ... Oct 7 2007, 09:06 AM |
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:
|
Lo-Fi Version | Time is now: 10th May 2025 - 01:21 AM |
Invision Power Board
v9.1.4 © 2025 IPS, Inc.