Dou you have a voltmeter?
If you do locate the battery disconnect relay.
Connect the leads from the voltmeter to the small terminals.
Have a helper push the switch. Meter should read voltage.
Have the helper push switch the to the opposite position.
It should read opposite polarity from the first test.
This should identify whether the switch is bad or the relay.
Another test again using a volt meter is to test whether the relay contacts are made or not. Connect one lead of the voltmeter to ground and the other to the large battery side of relay. Read and document reading. Then move the lead to the other large post. The readings should be the same if the contacts are made.