how to put wire connection to a RELAY.

Relay simply a secondary switch to trigger the operation of any accessory or any thing that needs power.
normally it has four terminals. an ordinary relay that are purchased in auto store has an assigned number in each terminals 30, 85, 86 ,87.

how a relay operates.

the 85, 86 terminals are interconnected to each other by a winding.  Naturally one receives a positive supply, the other one receives , negative supply. The 87 and 30 can also be used interchangeably  the 87 or the 30 may be the one to receive the necessary current to operate the accessory. When 85 or 86 is supplied by a positive or negative as the case maybe , since a winding interconnects each other , then a magnetism will occur, forcing either 87 or 30  to touch the other as the case maybe to transfer the current to the accessory needed to function or to operate.

Let me give example:

     if  85 is the one with positive supply from a fuse , and 86 has the negative supply coming from a switch.  If you will use the 87 as the carrier of the positive supply to be delivered to the accessory, then 30 must be connected to a fuse  .

in the above example , you can interchange the connection of 85, 86, and  the 87, 30. that means 85 receives negative, 86, receives positive, 87 receives positive, 30 delivers the current to the accessory.

It can be possible that the switch is supplied by positive (unlike the above example where switch has a negative supply) if that is the case , 85 is supplied directly by negative.  as explained above the 87 if you connect a positive to 87, then the 30 will go to the accessory or vice versa.

In the present day car, the relay has the same principle, but the wiring connection is somewhat complicated. however, there are also 4 terminals, though it has no numbers, but one terminal goes to the accessory , the other one goes directly to the fuse( 87 or 30 in case compared to the above) , the equivalent 85, 86 goes to some CONTROL MODULES of the car. Acceptably it is difficult to figure out by an ordinary car owner.

what you can do the relay in the present day car is to remove it and make a trial and error technique. that is , using the ordinary relay concept discussed above, you can do the following:

.  put the four terminal with 4 wires, then make assumptions that this terminal is the 87, the other is 30, the other is 85, the other 86,. this will take you a lot of variations. In this way you can prove that the cause of a failure of the accesory is the relay.