My Wheel loader (Volvo L90E) will not power off. As soon as the battery is hooked up it the cluster will power up. If you start it, it will not shut down unless you pull the main fuse. I don't think the ignition switch is the issue as it power up even if I hook the battery up with the ignition switch disconnected. I have also swapped around a bunch of relays hoping that would reveal the problem but it hasn't. Any other suggestions?
Volvos have a delayed shutdown function. It helps the ECUs store data and memory. If memory serves, there is a capacitor on the circuit board , it has slow decay to allow the ECUs to go to sleep, then the relay shuts down. Something must be keeping it awake. Any recent repairs? Heater fan, A/C compressor alternator conversion to the new style. Maybe when you next have it running, start shutting off accessories. See what happens.