Electrical Problem

[Mister P]

After years of browsing this site, this is my first time posting. (first-timer photo attached as required...lol). Took my 1983 911SC to Watkins Glen Vintage Racing this past weekend as I have for many years. One of the evenings I started the car and it stalled out after I let out the clutch. Checked fuel pump relay, battery connections, and pop-off valve. Car started after 3 - 4 tries. No problems rest of weekend. Back home I noticed a fog lamp had burned out. Removed the old bulb but didn't have replacement so I just put lense cover back on. Next morning NO electrical. Battery checked out as fully charged, but no door buzzer, no clock, no lights, and dead silence when I turned the key in the ignition. Any suggestion where I might start looking to remedy this problem?

[Discseven]

Hi Paul and welcome to PPF. Was initially thinking ground strap (engine to chassis) but that---I believe---is limited to engine electrical issues and not door locks etc. Is electrical from battery to fuse and fuse panel original? Any electrical system mods in car?

Nice car!

[Trackrash]

When I first go my car there were a couple of times where the electrical would go dead. Turned out in my case that one of the connectors under the dash that plugs into the harness below the instruments was bad. I learned that when this happened I would reach under the dash and hit the plug and I was up and running.
Not sure if this is your issue, but I thought I would share.

[86 911 Targa]

My first thought would be the red and brown wires from the battery
which feed the fuse panel.

Also the same for your battery cable to the starter and ground.

Let's have a look and check for corrosion or loose connections,
also battery voltage under load.

Also, the ignition switch which kills the lights, and
other accessories such as the AC when you start the car.

pm me as needed.

Best,

Gerry

[SpyderMike]

MisterP,

Most power comes in from the battery through a bulkhead connector to the ignition switch where is it then distributed back to several busses at the fuse panel. As mentioned, check the large red wire connections at the battery, then check the bulkhead connectors, then make sure the electrical section of the ignition switch is firmly seated and working properly. Your problem is somewhere in there most likely. Oh, and check the battery ground connection.

[steely]

Originally Posted by discseven

nice car!

+1

[wayne robson]

Hi you said next morning , no start, battery check was fully charged, are you sure
as your battery should read 12.6-7-8, fully charged cold with multi meter,
not 12 or 11.8 11.9, make sure this is checked with meter then do what others say.

[DanielDudley]

When you checked out the battery connections, did you disconnect them and clean the terminals ?

[Mister P]

Lesson learned. My assumption was that the battery was good because my multi meter gave me a reading of almost 13. I cleaned the posts, replaced battery cables and checked the wires under the dash. Took battery in to have it tested under load and found the battery to be shot. I replaced the battery and everything is wonderful in Porsche paradise once again. Thank you for all the suggestions. Very much appreciated!