I may have posted this here before.If so, I apologize. I have a 1999 911 coupe with only 30,000 milesbut which has its second new/rebuilt alternator in six months.. The center console dash lights flicker slightly when idling at 1500 rpm.. The headlights flicker a bit too as well as the roof lights etc. The radio flickers on and off like static when the lights are flickering. The dash lights behind the steering wheel don't seem to flicker as much.. When I rev the engine, while standing still,to 2500 rpm the flicker still persists, but if I go out on the road at 2500 rpm, the flicker stops. Weird huh?Apparently the grounds are all ok but the voltage drops ! when revving up, rather than increases. Extra weird huh? The voltage seems to go up again when on the road and theelectrical systemis under load. Any help, conjecture or magic wands gratefully accepted

 

I also have a 1999 911 with about the same mileage as yours.

I need to think about this maybe Porsche DOC will provide some insights.

It still sounds to me like a loose connection. on the other hand,

I had one occurance not on a Porsche where I had unusual engine vibration that came and went with some flickering on gauges. it was the controler for the car. The Porsche has a voltage controller as all cars do. The next step would be to look at that.I would think it would just quit, but mine hung on giving gremlins for about a year before the car went dead.

I am frankly guessing. I wish I could help more.

lee

 

The flickering in the lights gets worse when the car is under a load..such as when I put it in R or D (I have Tiptronic) but am still stopped at a stop light.Stopped at a stoplight, the flickering is of medium intensity when I am in P or N and gets more intense (and the radio really cuts in and out) when I put it in R or D. Makes no difference whether in manaul or Tiptronic. How do I get Porsche Doc to look at this posting?

 

I am frankly surprised he has not popped in. he does Porsche mechanics for a living. The high end stuff . He seems to give great general guidance.

I wish I could help more. If it gets worse under load, normal but not high vibration thenit is most likely not a loose connection. Sounds like the controller. i suspect a mechanic can hook up the CPU and get an error code. I know you can buy them for domestic cars but i do not know about Porsche.

If you were closer we could ring it out to check for loose connections and swtich contollers since my Porsche is the same year.

Sorry

Good luck to you on finding the problem

Lee

 

I must say, I haven't ever seen this problem. How old is your battery? Are the connections at the battery tight? A charging system is fairly basic, you just have to find which end is causing the problem. When did the problem start. Has it had any work done to it recently?