id say its your main Relay
have a listen to it when u turn it to on position (acc)
can you hear a click if not there a problem?
Google what it looks like.
Have you checked you earthpoints
-Rocket cover (passanger side) to body/mount
-harness earth to the thermostat
-your earth to you gearbox to cad body.
-Battery negative to body.
Make sure all these have good conection and dont have rust or anything not letting the have a good ground
Also check your fuses with a test light on either side of the fuse the two little.metail bits in between the fuse numbers make sure you trst light lights up on both sides.
Check your fuses in the engine bay compartment as well the especially the ones with the clear wimdows on the that are held in by screws. again touch either side of the screw with the test light to check for power.
You should be able to diagnose this quickly.