MVS Moderator and Volvo DIY fan Abscate looks closely at what fails on P80 ignition switches. If you’re having trouble starting your P80 Volvo, this shows you what is broken and what you can do to fix it.
Most of us have had to replace the electrical part of our ignition switch on high mileage P80s – I dove into my replacement from 2013 and this is what I found,comments on pictures
Executive summary – these switches can probably be put back into service by opening them up and cleaning the points inside the gray cover.
In the 5th, you can see there are white plastic eccentric cams – these open and close points which connect the various terminals based on switch position. There are two radii of points and two plastic cams that open/close them by the way.
In the 7th, you can see the ball bearing and groove that limits the rotation of the switch – Im guessing this wears out and the ball pops out, relieving tension and giving the ‘loose spinning key’ scenario
Worn cams will allow spinning, and perhaps are root cause of the points not fully closing, creating electrical chaos.
OF course, points can pit and grunge, like mine were, so Im guessing thats more likely how they fail.
Oh, important safety note. Some of the points are all normally closed, so don’t put this back into car to test it without the cam in place – that could cause all sorts of havoc.