Can anyone tell me what these things are on a 1974 late model 260z

Unknown item 1 is on the passenger side mounted above the frame rail.(silver box mounting screws on top, might have been black in the past) 

Unknown item 2 (rectangle metal box with wires going to it) is under the black cover on the passenger side in front of the battery on the fender well. It is under the black cover on the back side (towards back of car). 

item 3 is on the opposite side of item 2 under the black cover towards the front of the car.(smaller metal box with wires connected)

Item 4 (the silver box on the firewall)  is on the firewall on the passenger side

 

I am trying to find out what they are and then find replacements so I can add them to my back up parts in case they fail.  

 

Thanks

 

The relay locations are shown in the Body Electrical chapter.  The 260Z has the inhibitor relay also.

https://www.classiczcars.com/files/category/12-260z/

The wiring diagram will have wire colors which can help.

https://www.classiczcars.com/files/category/1-wiring-diagrams/

Some of the relays and devices have numbers printed on them.

Thanks Zed Head