Rewiring the heater
Part of the previous wiring installation. Getting the wiring right is key to reinstalling any kit when multi-strand cable looms are involved. With older systems the wiring may differ from new colour codes, so make notes and take plenty of pictures.
With the batteries off, the first thing to be disconnected was the red positive lead running through the main 25A fuse into the battery isolator switch.
The next job was to isolate and disconnect the negative lead, and this was the brown cable on the negative battery terminal. Ensure any other cables affected are reconnected and secured.
After removing the wiring cover, the glow plug cable is exposed. This bolts on to a small stud on the heater body. To protect the contact head and terminals, I then put a bit of tape around them.
Now the main terminal block from the control box could be removed, leaving all wires to the heater itself disconnected.
Where twin wires were the same colour in the existing installation, a piece of tape was used to identify separate wires. It was some time later before I had to reconnect the cables, so taped marks helped me identify the right connections.
The various connector blocks were disconnected but had not suffered the corrosion affecting the other parts of the system due to the liberal use of a coating of silicone grease.
The multi-core cable which would need to be lengthened was isolated from the rest of the wiring and cut.
All connector blocks and terminal contacts were labelled and numbered. The male spade terminals were carefully removed from the block with a precision screwdriver. New ones would need to be fitted to the lengthened multi-core cable.
A waterproof multi-terminal box was fitted into the bilge for connecting the extended wiring runs. On the right side are the old cables in and, on the left, the new cables out.
Identifying and finding the rightsized new spade connectors took a while, but in the end I found www.componentshop.co.uk to be very helpful and reasonably priced.
The control module was fitted to the new wooden pad previously epoxied to the transom. (See ‘Fitting the mounting pads’). It was made large enough so there was a clear area for securing cable runs with clips.