The other thing is if its an 87 royal this is in the wrong place for educated help. I stopped to look because it said "2nd gen" But electrics to start with is basic same ole stuff.
If you are shorting across the starter solenoid and get nothing, you do not have enough voltage available at the component. So either power wire connections or ground all the way thru. IE: at the motor, at the block at the battery at the solenoid etc