99' S80 6cylinder electrical issues-no start
 

Hello everybody! I'm an auto tech from columbus, oh. I was hoping someone on this forum would be able to help me trouble shoot this 99 volvo s80 im working on.

So.... customer had the vehical towed in. She was driving down the highway around 65mph when her dash told her the abs failure occured and to stop the car. So she did and shut it off. After a few mins she tried to restart the car and it would not crank. This is when she had it towed to us.

When the car arrived I put a battery charger on it. When i turn the key to the on position the head lights and tail lights and turn signals start flashing, all the relays under the dash are continues clicking, the dash lights up and the display shows srs failure, abs failure, the red ! is on, and after about 5 sec the dash will die and only after it dies the check engine light comes on. I have tried scanning it and no codes.

When I tried to crank it the power comes and goes at the same rate as the headlights strobing and relay's clicking. Ive put my power probe to the solinoid wire on the starter and it will crank as it is suppost to but still no start. I have tried looking for a broken ground and even cleaned the ones i have found. The battery is in good shape and holds its charge and terminals are clean and tight. I tried swapping the computers under the hood but had no change so I put back in the originals. I thought maybe the ignition switch could be bad? All the accesories are not affected by this problem. The radio, climate control, windows all work fine. I have searched forums for anyone having the same problem but no luck. I will post a video this evening showing the symtoms but any feed back would be highly appreciated! Thanks!!!

I had the same problem and symptoms on an 1999 S-80 I HAD. They are buggy to say the least. The flashing lights you describe are symptomatic of the anti-theft system kicking in. I found a bad ground had fooled the system into thinking it was being bypassed and therefore, stolen. You should find 3-4 black ground wires under the hood near the strut tower. Right side I think. It turns out these are the grounding wires for the computer. Check the resistance. If not that, the ABS computers are infamously faulty. Good luck.

Hi. I have that exact same car with that exact same problem over here in Sweden. Have checked all ground wires, checked all positive connections I can find and the battery are new but nothing have helped so far...
Did you find a solution for that car you working on?