81 Volvo: Key out of ignition but car still running

I have an 81Volvo 240 sedan with a little more than 200k miles on it. I’ve had this issue with the ignition for several years now. Sometimes when I turn off the car with the key as normal, the car keeps running as if nothing happened. I’ve tried several fixes:

  1. moving the steering wheel violently and put the car out of park
  2. replaced the ignition switch.
  3. replaced the ignition switch relay.

Now the only way to turn the car off when it does this is to pull the relay under the dash. When I reconnect it, it works fine. But, I’d rather not have to pull the relay everytime I want to turn off the car! My uncle owns many volvos and has worked patiently to help me troubleshoot this issue, but we are out of ideas! Any insight is appreciated.

Thanks,
Hilary

Here are some diagrams that may help.

Buy a new relay for the one you are pulling. Next time it happens pull the relay and replace it with the new one. Perhaps the relay itself has old sticky contacts internally and is the source of your problem.

You need a new wiring harness. Volvos of the 80’s, until 88 had biodegradable wiring harnesses in the engine bay. Cars have been known to self ignite while parked in the garage and burn down the house. A new wiring harness imay be available on line. The Volvo part number # is 3515364. You might find a good used one thru this site. He comes highly recommended. Good pluck!
http://www.davebarton.com/volvoharnesses.html#availability