Fuses in Battery Box 90V8i

I have two fuses in the battery box and I'm not sure what they are for.

Two leads come off the +ve battery terminal, one blue, one green, go through the fuses through a relay and disappear into a loom. Could they be for the 12s & 12n towing sockets fridge and charging circuits?

Reply to
hugh
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Probably - 12S only. Not 12N which is full of the normal lighting circuits.

As to how it's wired up, it rather depends on who did it and whether there was any intention of sticking to 'norms'. Mine looks normal at the battery end but is very far from that at the rear. Quite how it has been wired may depend on how the trailer which it was originally intended to be used was wired: there were several (3, I think) standard trailer setups. I wouldn't assume that it's standard.

Check that fuses are OK - not blown and with clean contact areas or you risk wasting a lot of time.

You probably want to start by determining what controls the 'relay'. It's very unlikely to be manually controlled and could be either a normal relay controlled off the ignition circuit or a voltage sensitive relay probably sensing off the battery itself. Reading what's on the relay case may give a clue.

Which it is probably doesn't matter - just confirm that the relay output is only 'live' when the alternator is charging. Simply, there should only be an output when the engine is running and the ignition warning light is out (but see below, too).

Then disconnect the relay outputs in turn and see which comes out where on the 12S socket. I'd suggest that you check that there is an output coming out of the relay or, again, you could be wasting your time. Don't assume that the earth connections are OK. You should then be in a position to see if it looks like anything standard - assuming that you know how 12S sockets are normally wired.

If you don't ....

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Your installation could be like the last diagram on the page. (This looks as though it could give a relay output if the ignition switch is 'on' which is a little less sophisticated than what I mention above. It's wired as the earliest of the 3 standard setups.)

Reply to
Dougal

In message , Dougal writes

Thanks Dougal, that's a really useful link. The sockets were installed by a Land Rover dealer and are "standard".

The obvious thing to do is to pull each fuse and see what happens to the voltages on the 12S pins. I am about to pick up a caravan which has the new 13 pin system so I will be using a converter cable. On my other van (early 2008)pin 2 on the 12S was left open and according to the handbook this was so it could be earthed if the towing vehicle was using that circuit as a connection sensor. I'll have to check what the converter cable does, but in the short term if I can pull the appropriate fuse that will avoid any drama.

Reply to
hugh

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