Relay Assumption?

Over the past couple of years of having my Octavia I have had some electric faults being instrument cluster (Fuse 15), interior light not working, problems with heater fan and rear wiper motor. Over the few days that have been and gone I have done some work and research and I'm hoping I have found the answer.

Rear Wiper Motor: Works when connected direct to battery but not through the wiring on the

tailgate.

Plug and wires are non defective and fuses have not blown. Multimeter picks up

a current when wiper stalk is active.

Interior Light: Does not operate when doors are open. Fuse not blown and light bulb good.

Heater Fan: Intermittent fault working and not working. Wrong speed and struggling.

Fuse good and multimeter picks up current. (Resolved) Dirty contacts.

Instrument Cluster: Works with Fuse 15 removed but clocks reset when engine is restarted.

Dials stop working when Fuse 15 is replaced. Dry joints found on circuit bored

have been re soldered but no resolve. Fault still remains.

Having obtained a wiring diagram it appears that the above instruments run through the same relay plate but unfortunately does not specify which relay specific to each item although the diagram of the relay look the same. Another point to make is that the relay does not make clicking sounds anymore which suggests that it or they are not energizing hence I believe the fault.

If I am right in thinking that the culprit is a relay or relays I am hoping to solve the above and share the info with all of you but to do this I need to know what relays do what. There are relays under the drivers fascia steering wheel area and in the rear of the engine compartment. I'm hoping I have the answer. IF anyone has info on relays please let me know.

Ade