LOL, yes, it is a Relay
On the inter fender the larger battery positive cable is connected to the Starter Relay(also called starter solenoid)
On this relay is a smaller post labelled with an "S"
When the "S" post gets 12volts this relay closes and sends Battery Voltage to Starter Motor from the other larger cable, and post, on this relay
Battery"+"----(large cable)-----------Relay-------(large cable)-----------Starter motor
ignition switch-----(small wire)----------/
When you turn the key to START the ignition switch sends 12v out to Starter Relay "S" post.
BUT.......................
That 12v runs thru a Safety switch to prevent engine from starting "in gear"
On a manual trans vehicle this is the Clutch safety switch, clutch pedal must be pushed down all the way to pass that 12v from ignition switch
On an automatic they used an NSS(neutral safety switch) on the drivers side of transmission, in 1987 it would have an A4LD trans, and the NSS would be a screw in/plunger style switch just above trans shift rod
Trans must be in Park or Neutral for this switch to pass the 12v to starter relay
Battery----------ignition switch--------safety switch-------------starter relay(solenoid, lol)