Topic: Horizon/bmc cockpit wiring diagram?

Lopez    -- Oct-25-2021 @ 2:36 PM
  Anyone knows where I could find a wiring diagram for the cockpit so that I can start making sense of this? None of the dials are working or in fact nothing is other than the starter...  LOL


spiderman    -- Oct-25-2021 @ 3:55 PM
  I think this might help  LOL

Stingers    -- Oct-25-2021 @ 4:01 PM
  Oh dear - its a bit of a rats nest in there. Sorry I can't help with a diagram but noted that a white wire is not connected to anything and also a yellow wire, although that is taped off. You also have very old types of fuses fitted and I know from experience that they can be troublesome in that the pieces of spring metal holding them can become weak, causing a bad connection. I helped out a Freeman owner once who had a just such a problem.
Good luck,

Edited to say that your horn has only one wire going to it so I guess that's also out of action.

This message was edited by Stingers on Oct-25-21 @ 5:03 PM

Greybeard    -- Oct-25-2021 @ 4:28 PM
  wow,, straight out the "Stevie Wonder big book of wiring.

as has been said already,, multiple problems there, might be prudent to start from scratch once you have the proper wiring diagram.

try to use more than just red wire,, makes it much simpler to follow when chasing a fault.
good luck.

my appearance is down to me, my attitude is down to you.

annville    -- Oct-25-2021 @ 4:31 PM
  There are no wiring diagrams as such as different boats have different requirements. first i would remove every thing on that board its all sub standard, first what do you want to power? then will it run from domestic battery or engine battery, you will need two battery isolating switch's you then need a 50 amp fuse box with a 10 amp fuse? wired on battery side of switch this is to run bilge pump, you then need at least two prs 50 amp cables red and black the two black go to two separate  earth connecting bars, you then need three fuse boxes one for ignition switch supplied i.e. wipers, horn, engine temp, fuel gauge and one for engine battery supplied i.e. nav lights, demister, gps, anchor light, and one supplied from domestic's battery bank, lights, tv, water pump, heater, deck lights etc the domestic earth should be on separate earth bar to engine earth bar. write down the coloured wires with a diagram on a piece of paper as you wire items up along with fuse number, and dip smear all wiring ends and contacts with Vaseline. Wiring is very therapeutic and satisfying. with out knowing what and where you are fitting? .try to keep wiring with white trace for ignition, purple for horn, blue for lights, and red for can be black or brown no trace. John

This message was edited by annville on Oct-25-21 @ 5:41 PM

L'sBelles    -- Oct-25-2021 @ 6:13 PM
  That is about par for the course. I have 12 fuses on my main fuse board with all wires coming in being red and all outgoing wires are! Guess what? None of them are marked! When I get around to the rewire it will be a case of pulling out the fuse to see what stops working!

Boats are not like mass produced cars where pre-made looms are fitted in the same position in each example according to a diagram. Even boats of the same model from the same yard will be different depending upon who wired them up and as John says if you are doing a full refurbishment and you have dodgy connections anyway save yourself the time and grief and start again from scratch using different coloured wires and noting what each one does as you fit it. That will make fault finding a whole heap easier later on.

Lopez    -- Oct-25-2021 @ 6:20 PM
  Haha. Yes, ultimately that's what I'm doing. But before I rio everything out I got to reverse engineer what is connected btonwhat and how...

Lopez    -- Oct-25-2021 @ 6:22 PM
  Stingers yeah. Loads of wires disconnected, afew that untraced to the engine aren't connected there either or straight up chewed up or cut, also the alternator is disconnected and the engine won't start as of today... I can hear a solenoid clicking in the background. Haha

Lopez    -- Oct-25-2021 @ 7:03 PM
  Ok so I'll carry on working out things then. Now for the stupid question, can someone point out what the switches/lightabdi or are supposed to do? That would help me out work out what should be connected btonwhat and test for voltage/resistance/etc.

Fwiw, when turning key to position 3 the top centre red light lights up, so I guess it's glowplugs? And when going into 4 to start the bottom red light lights up.

I'm getting a solenoid clicking of sorts in both positions 3 and 4


L'sBelles    -- Oct-25-2021 @ 9:26 PM
  I can't see your ignition switch in the photo but I am guessing it is one of the Lucas types with 4 positions. The basic function is shown in the attached.
Position 1 - All off.
Position 2 - Run. So all ignition switched feeds are live in this position.
Position 3 - Glow plug pre heat. Glow plug light illuminated.
Position 4 - Start. Glow plugs remain live and starter solenoid is activated.

Without seeing your actual switch terminals it is difficult to be more specific as there are so many different types. It might even be a Land Rover switch.

The clicking you hear in 3 and 4 may be a relay switching on the glow plugs but you should have a heavier sounding click in position 4 of the starter solenoid. It could be a connection issue or the solenoid itself. Check to see if it is the type with the manual plunger to rule out the high current side.

You will also have a warning light connected to the alternator which should come on in the run position but go out once the alternator starts charging.

As for the rest who knows? I'm afraid it is a case of reverse engineering the wiring to see where that leads you as it is almost certainly not original and has had decades of modifications carried out by people of varying competence.

This message was edited by L'sBelles on Oct-25-21 @ 10:35 PM

PCL023    -- Oct-25-2021 @ 10:30 PM
  In position 2, ignition on, if two of the lamps light up, it’s likely your charging system has two alternators installed, one for the engine battery the other for the domestic battery/s. These should go out once the engine is running after applying some revs. Another lamp could be glow plugs, engine temperature warning or low to no oil pressure. The only way is to trace them back to origin. Using a multimeter can help here, for a no power continuity test, as I see there was at least one wire that started off as a brown wire and changes to yellow in the original photo.



This message was edited by PCL023 on Oct-25-21 @ 11:31 PM

Lopez    -- Oct-26-2021 @ 8:17 AM
  Ok thanks everyone. Seems i got right the ignition at least, and L'sBelles, you were right that i got the Lucas ignition 'switch'. Had come across the same connection diagram you posted and found it useful. Thanks for digging it out.

Heading back to the boat to carry on guessing what's what. Oh the joys .

annville    -- Oct-26-2021 @ 10:25 AM
  Hi All as Lasbelles said plus 2nd position is also oil light charging light, if you are getting a clicking sound its because you have corroded/loose connections you should only get one click as solenoid activates to switch larger currant ie heater plugs ,starter motor most gauges will have s,+ this pos side with e,- is earth side or it is wired to sender as in oil warning lamp sender/temp sender, or in the case of ign warning light goes to ign term on alternator or where thinnest wire is connected, the W term on alternator goes to rev counter. John

This message was edited by annville on Oct-26-21 @ 11:31 AM

Lopez    -- Oct-26-2021 @ 11:32 AM
  Hi Annville. I got 2 relays So i get 2 clicks. So far I've worked out 1 relay does the starter and the other opens the circuit between the alternator and the batteries.

Found a pretty useful wiring diagram for the starter and looking at it the live wire from the ignition to the starter is not connected, so that may be why the nonstarter. Looking for the wire as we speak.

Thanks for the tips regarding gauges, etc. Btw

Diagram for future reference as someone might find it useful is here

And his website is full of really useful stuff so I'll promote him a little

Lopez    -- Oct-26-2021 @ 11:53 AM
  Ok, that was it. Engine is now happily purring along.

Weird thing, the starter/ignition wire was actually connected to the alternator, so on the one hand I was wrong about the relay, and in the other, anyone got a wiring diagram for the alternator? Haha  LOL

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