I own a 1999 s80 and I'm experiencing some issues regarding the electrical functions. Yesterday i started the car and everything sounded normal as it usually does. A few seconds after I started the car the speedometer and all other displays turned off. The Windows couldn't be rolled up and the unlock and lock buttons weren't working as well. At first I didn't realize this so I started my drive home and realized when I my blinker wasn't working. I tried to turn the lights off but that function wasn't working either. I looked up what was wrong and found that there could have been a problem with the alternator. But the article said if this was the problem the car would have shut down. I managed to drive all the way home without any other problems with the car, no weird sounds coming from the car or anything it drove perfectly fine. I also read the battery could be the problem but my car started up fine and now, even a day after it still starts up perfectly fine. Also, I was able to use functions such as the radio or AC, which I found also stayed on when the car was completely turned off.. Any suggestions??

 

wondering if it could be the ignition switch. Did the car go back to normal after you shut down and restarted? anything change if you wiggle the key?

 

No I tried shutting the car off and starting it back up and same result... Electrical functions work for a few seconds and then shut down

 

This problem sounds like your CEM (Central Electronic Module) is misbehaving when it gets too warm. Once it cools, the problems disappear.
My 2004 S80 (I am the original owner) started having the following problem at age 9:
First the interior lights come on and the dashboard readout (lower left corner) says LEFT REAR DOOR OPEN. I reach back, open & close that door but soon afterwards, the same thing happens again. Stopping, shutting off the engine and restarting seem to work briefly however eventually, what you describe occurs. When it's hot enough, this'll happen every 3-5 minutes then the dashboard shuts off (no lights, speedo, tach nothing) the headlights come on and will not turn off EVEN IF THE ENGINE IS SHUT OFF (I once had to disconnect the battery) and the engine defaults to limp home mode. The windows stop working, turn signals also go dead.
It's always related to heat build up, very common in the summer.
I first believed this was the ABS module, so I removed it. The same thing kept happening. After reinstalling the ABS unit, I poked around this forum and located a description of what was happening to my car almost exactly, from a forum member in Vancouver.
S/he removed the CEM, installed heat sinks and a computer fan, and solved the problem that way.
I did it far easier and cheaper; I took off the lower dash panel from underneath the steering wheel; it occurred to me this panel was allowing hot air to build up, so I jury rigged a paper tube and masking tape between the left footwell ventilation outlet (it's on the right side near the accelerator pedal) over to the CEM.
This directs air onto the module.
Voila! Even in 90 degF weather with the fan set on setting 2 of 5, the electrical problem does not occur, even without the A/C compressor operating.
I assume even a minute of A/C cooled air through the lower vents, directed straight onto the CEM, will cool it and eliminate the problem. So far, however, the gremlin has not resurfaced WITHOUT A/C since I did the above. My guess is the CEM in my car will tolerate up to about 95 degF under the dash and operate normally. The lower panel was allowing still, uncirculating air warmed by engine heat (or sunlight when parked with closed windows) to become too hot. I am guessing the removal of the lower dash panel is probably enough to allow enough circulation to lower temperature build-up. To be sure, however......
Fabricate a 1.5"/4cm diameter cardboard tube(s) with masking tape and attach it/them. Use two pieces to adjust length, if necessary, and pop out the ventilation outlet from behind. It will both come out & reinsert easily and snugly once the tube is taped onto it. It will sit high up and behind your feet and will not interfere with operation of the pedals.
Yes, it looks a little unsightly BUT removing the CEM will not be easy. Having it rebuilt (by say, BBS Reman) could be $600+ and reinstalling it properly could be a CHALLENGE. There are quite a few relays involved, once the unit has been unplugged and removed from under the left side of the driver's side dashboard.
Masking tape and medium weight advertising mailer paper (what I used) will be super cheap (or free!)
To test for this possibility, remover the lower dash panel above the pedals (it snaps out easily) then turn a hot, blowing hair dryer onto the CEM (you'll see it on the left) while the engine is running from a cold start. If your problem occurs after a few minutes, as you described it, you have your solution.