Relay madness

Hi forum,
I just bought a 94 T4 trophy in great condition except for a minor electrical issue.
The previous owner left two relays in the glove compartment: 80 (grey) and 167 (white).
Any idea why anyone would leave them loose and where they  should go?
Would this explain why I cant get the charge light to stay on when plugged into 240V?

In reality the only person that can answer is the previous owner. We don't know if there are two empty relay sockets somewhere in the van, or whether they are spares for ones already present.

However, your description of the problem is slightly unusual. When you say that you can't get the charge light to ~stay~ on, what do you mean? That it comes on and then goes out? If so, I doubt that these symptoms would arise with missing relays - you would far more likely just never see the charge light come on at all.

Generally the discrete relays at the front of the van are more typically associated with leisure battery charging from the alternator than from the 240V based equipment.

Thanks mojo. There appears to be a full set of relays above the fuses. The leisure battery appeared to be flat according to the battery meter on the zig. When the van was plugged into 240V, the charge light was not coming on. So I thought I would charge the leisure battery overnight using a separate mains charger. Once I did this, I tried the mains again on the van and the green charger light came on for a short time and then went out. All the lights work on the 240V setting but when I switch to 12V on the zig, I get no power to internal lights. The leisure battery has about 13.5V across it when disconnected and the normal vehicle battery has about 12.5V. Could theses loose relays be responsible or is it more likely to be a fault with the mains transformer (T7)?

Does this look like a full set of relays? There is an alarm fitted but I think one relay may have been removed to stop it from sounding by accident but dont know why there is a green cable dangling below?

Hi.   

I think the relay thing is probably a proverbial red herring! Unless there has been some weird modification the relays should have no bearing on the operation of the Zig unit.

simon wrote: is it more likely to be a fault with the mains transformer (T7)?

Are you sure it’s not X7?    

There appear to have been several different control panels fitted but if yours has a “Charger on” light (mine hasn’t) it should be powered from the “LED” connection on the power supply unit. Excluding the possibility of an intermittency in the wiring that light going out is a sure sign the  power supply is not working.

simon wrote:Thanks mojo. All the lights work on the 240V setting but when I switch to 12V on the zig, I get no power to internal lights.

Normally the control panel will just turn the 12V system on or off. A quick check to see if the Zig is working is to get it into the state where the 12V lights are on with the mains connected and disconnect the leisure battery. If the lights stay on the Zig is powering them.

Assuming the lights go out you can prove the Zig is faulty by confirming that the mains supply to it is switched on, then disconnecting the output leads and checking for 13.8 volts on the output connectors. If that is OK connect like a light bulb to the output and check that it lights up. It’s possible that the power supply comes on but can’t supply any current which could explain why the green light comes on and then goes out again.

Brod.

Thanks Brod. Zig is definatly working today. Green light stays on and runs internal 240V light as well as all the 12V lights as well, even when leisure battery is disconnected (top tip, thanks).
But when I switch Zig to 12V, internal 12V lights go out. There is 13.V across the leisure battery and power gets up to and across the fuses in the engine compartment. This little relay next to the fuses works well. I cant understand why the leisure battery cant run on its own. The battery test on the zig gives a green light for the battery and I don't think it lacks any oomph as its quite new as well. I'm mystified.

Hi Simon.  

A couple of points:

simon wrote: Green light stays on and runs internal 240V light as well as all the 12V lights as well,

The Zig has nothing to do with the 240V lights (or sockets). They run directly from the 240V input as does the Zig unit. The Zig takes 240V in and outputs 12v (well 13.8 actually) to run the 12V equipment and charge the battery at the same time.

simon wrote: But when I switch Zig to 12V, internal 12V lights go out.

Not sure what you mean by “switch the Zig to 12V” and I’m not sure that the switch does what you think it does.
 Normally the switch only turns the 12V system off or on so when it’s on the 12V lights will work and when it’s off they won’t.  From your description it sounds as if it’s working normally (unless I’ve misunderstood something).

Brod.

PS:
Just re-read the last post. Is the problem that the 12V lights only work with the mains connected?

If so you can double check by doing the leisure battery disconnection test in reverse. That is to say get back in to the situation where the mains is connected and the 12v lights are on (the 240V lights are actually irrelevant as far as the problem is concerned).

Make sure that the leisure battery is connected and then disconnect the mains. The 12V lights should stay on. Post the result and somebody will come up with some more suggestions.

Hi all,
I think we are getting somewhere now. Your idea about doing the check in reverse helped a lot. Once I turned the mains off, the lights when out.
So I disconnected the battery and then reattached the mains. I then tested the charge across the disconnected leisure battery terminals and only 0.02Volts are detected, even though the charger light is brightly on and the internal 12V lights are blazing. So as Frank suggested on the trail I left in "Help with Zig please", I guess there is a faulty connection between charger and battery terminals. 
I then tried to detect voltage across the black disconnected leisure terminal and the engine red terminal and there was 12Volts. The opposite way round (disconnected red to engine black) got a reading of 0.02Volts again. So I suspect its the red lead connection somewhere. Does this make sense?

Hi  

simon wrote: So I suspect its the red lead connection somewhere. Does this make sense?

Yes. There should be a connection between the leisure battery positive and the positive terminal on the Zig unit. Yours is clearly missing.

Firstly, just check that the negative terminal on the leisure battery is connected to the vehicle bodywork.

There will be at least two red wires connected to the positive terminal on the leisure battery. I don’t know the layout of the Trophy so these may be connected at the battery or you may have a single wire that is split further down the line.

It’s going to be a case of tracing where the wires go. One will go to the starter battery via a relay (the spit charge relay), it’s the other one that you want.  This will go to a fuse and possibly (but not necessarily) a relay and then to the positive terminal on the Zig.

Sadly unless someone that knows the layout of the Trophy reads this and chips in it’ll be a case of searching for the wires and components however here are a few  tips:

In my experience AS rarely connected to the vehicle fuse or relay box so look for junction boxes that look as if they were fitted after the vehicle was made.

Try finding the wire at the Zig end and try to trace it backwards. You should find one wire going toward the control panel and the other (the one you want) going in the direction of the leisure battery.

Check the connectors on any fuse or relay you find. Problems are often caused by burnt or corroded connectors rather than the component itself.

From you last post it sounds as though you need the van at the week end. If you can’t fix it in time you could always run a new cable as a temporary measure. Then fix the original fault at your leisure.
You just have to get hold of some 20A+ cable (4mm or preferably 6mm)and run directly from the positive terminal to the Zig positive via a 20A fuse. You can get an inline fuse holder from Halfords (other accessory shops are available). Just make sure the fuse is fitted as close to the battery as possible. It’s my understanding that the habitation disconnection relay was not compulsory in 1994

Brod.

Wow.Thanks for such comprehensive support and suggestions. This is the sort of advice that makes this forum really worthwhile. I will respond as soon as I discover the problem and resolve it. Have a great weekend. 

I had a problem the other week with our 1999 T4 Topaz where the 12V habitation electrics were not working. It was fixed by cleaning the fuse up by the leisure battery under the bonnet. It looks like the contacts had got a bit corroded (they looked OK, just grey rather than shiny) and were not passing enough current/voltage.
The fuse and relays for our leisure battery are just to the left and above the batteries under the bonnet.

Hope you get it fixed.
Cheers, Dave

Thanks Dave, checked fuses in the engine bay a few days ago.
Thanks to Brod and boxerman, I can now say PROBLEM SOLVED.
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Tracing the wire diagram someone else prompted me to and using Brod's approach, I excavated under the fridge to get to the transformer. Delighted to find that the red cable from the battery have merely become detached from behind the transformer. I have had a great deal of trouble putting it all back together again as when I twisted it back into position to rescrew it back onto the little shelf it sits on, the fixing became detached again. Very frustrating to have to unscrew it all again but now its back on, its all working fine. One mistake I made was switching the two red cables over accidentally. But now its all the right way round, its all working.
THANKS FORUM  

Job well done.
Is the transformer secured to the floor? If not, those spade connectors could become detached again.

PB

Hi.   

  

Good forum this init!

Brod