Porsche 911 electrical

While driving on the highway, I got a whole bunch of warning lights. Mechanic replaced alternator, but while returning from the shop, I again got flash of several warning lights, though they went out in a second (seemed to happen especially in a hard right turn). This continued intermittently for several months, though it hasn’t happened recently. Now, however, each time I start the engine, the SRS warning light comes on and stays on for about 90 seconds. It then goes out and is fine until next start. Additionally, on two recent occasions, when I started, the gauges were all dead. They started to work after about 15 seconds, then the SRS light came on as before. Battery is about 3 years old. Checked voltage before start (11.8v) and after engine running (13.6v). Ideas?

Year? Have you tried posting this on 911 forums? They’re pretty unusual beasts…

Check all your ground connections and battery connections. Also, where the hot wire ties to the starter. Cables could be bad and corroded inside the insulation where it connects to the battery. Check hot wire insulation and make sure it’s not scraping and bare anywhere.

The 11.8 volts you saw is not good. A good battery with a good charge on it should be around 12.6 to 12.8 volts. The running voltage might be okay but it should be slightly higher if the engine is running around 1,500 RPM. It should be more like 14.6 volts.

The warning lights and dash problem are due to another issue. The warning lights could be turning on due to a problem with the ignition switch or in the power wiring to it or after it. You need to check the power between the panel near the battery and the dash fuses. Since this is an intermittent problem it might be hard to track down. The trouble might be with the connectors to the dash for the power supply to it.