Welcome to the forum, Mike
In
this thread you will find info for the
ESSEX coach plus many other items.
I would pull the relays one at a time and see if it stops the other from chartering.
Have you had a lot of rain wiring may be short at light wiring location from corrosion or wires short to the chassis frame, is the bay where relays and fusing damp.
There are fusing and wiring links in the links I gave you, look under coach or in the engine area and front end and see if loose wiring to frame possibly.
Wiring diagrams for some of the relays your talking about.
You have a little to consume will check back later plus someone else may help also.