Ford Auto-Sleeper Legend GL

-mojo- wrote:

I can't see all of the photo because the forum software chops off the right hand side, but it looks to me to be just a standard 70A N/O relay.

Reply: Are you using a small monitor to view the forum? as it looks fine to me this end, and I'm on a 24" monitor.

However, the problem may be more complex than just needing the relay replaced. Buzzing is not a typical failure mode for a relay (typically either the coil fails, or the contacts erode so much that they no longer make contact, or the N/O contacts weld themselves closed). The second of these can lead to "arcing" type sounds, but that's not really similar to "buzzing".

Reply: The contacts seem ok, but I will give them a clean and reinstall it to see if it makes any difference, I don't think it's arcing, its a constant buzzing, so I guess you could be right on that point and it could be the internal coil of this relay, if that's what your pointing at.

The problem you have sounds more like a failure in the circuit that energises the coil (across terminals 85 and 86 in the diagram on the top). If you can identify what the relay does it may be possible to diagnose further - unfortunately there are often three similar relays on a typical A-S of that era, and they put them in different places, almost at will, so pinning down which does which function isn't always easy...

Well this one is placed behind the electrical panel, I'll add some more images below to show you where it is installed, I have no idea where, if any others are installed.

Peter Brown wrote:

I'm guessing from the age and model of van that the relay is used as a changeover relay to disconnect the batteries from the habitation circuitry and connect them to the fridge when the engine is started.

You could be right, the van is a 1996 model 2.5 Diesel ford transit. the fridge is located below the control panel.

The relay is energised by the D+ output from the alternator (as is the split charge relay) so I expect that either your new alternator has a different D+ output or it hasn't been reconnected to the habitation circuitry.

I had the alternator fitted while I was on holiday in south west Wales last month, was pretty costly too, if had gotten done at home wouldn't have had to pay so much for a new one.

But as far as I am aware the alternator connects in exactly the same way as the old one did, but it didn't buzz when first fitted and has only started buzzing a few days after it was fitted.

Peter Brown wrote:The convention at the time showed yellow as the colour of the wire to the alternator (or ignition in earlier models) to pin 85 or 86 with the other in black going to the vehicle chassis (you can see all the blacks commoned up in your photo.  If the relay is definitely the source of the noise it is either faulty, has a poor feed from the alternator or a bad connection to chassis.

Peter

inspiredron wrote:You can check the relay by putting 12v across 85 and 86 and listening for the click or using a meter to check that 30 connects to 87.
I would guess that the relay is OK and that the problem is a loose connection on either 85 or 86, as Petef suggests.
To my eye the red wires are too slim for fridge or battery charging. Might it be the automatic retraction of an electric step when the engine starts? Or perhaps it is responsible for sending 12v to anothef relay in the control panel to switch off habitation electrics when the engine stsrts.