starting issue - ignition - Leisure - Diesel Westy

[Hacksawbob]

Trying to further diagnose starting issue. I had the leisure battery out over the weekend just to check things over. There was something that I was un-consciously aware of but didn't start thinking about it till I had the the relay under the seat off. There is blue wire that goes to the relay. As far as I'm aware this is the alternator "engine running signal" to the split charge relay. there is a piggy back spade that goes back into the van chassis I think this takes the running signal to the fridge relay.
Anyway when I have the non starting situation the ignition is to start position, I hear the click from the starter relay and then half a second later I hear the under seat leisure split charge relay click in.... the engine does not start but the split charge relay kicks in. I am not sure if this is relevant to my non starting issue or if its normal, if it isn't then I can start looking into it a bit closer. I have done quite a few of the usual checks:

Previous history.
Engine changed September, previously no starting issue.
Battery earths cleaned and checked, positive to battery replaced, gearbox earth replaced,
I added rear starter motor earth straight to battery.
I replaced with a new ignition switch, tested with spade from back of starter spade to + on battery starts fine, across battery checks 10Volts during successful starting.
I did manage to catch it with a once during whilst non-starting and it was 8-9 volts from starter spade to battery, but its hard to catch it, usually its first thing in the morning and I need to get to work.
80% of time it starts straight off or I need to rock the the key in the start position, after 4th 5th attempt it fires up no problem.

[Aidan]

sounds like ignition switch you can take the cowl off and access the plug to the switch, remove plug and hot wire it
call me for details or read the post below about ignition switch that will explain the wiring

[Hacksawbob]

Thanks Aidan, if I hadn't changed the ignition switch I'd be inclined to agree, I'll give the hotwire a go and see what occurs.

looks like maybe the post removed?

[CovKid]

Blue wire/s goes to 86 on relay - 85 is the earth to make that side of the circuit energise and triggered as you say, by alternator. Once it does, it passes through the current to leisure through terminals 30 and 87 - 87 also supplies fridge power since it then only gets its power when vehicle is running (or should do). Some relays haver an 87a - this is usually live when relay is not energised, going off when it is. Usually if you have a solar trickle charger, thats a good place to connect it as it only works when alternator isn't charging - vehicle off.

This may help: http://www.keithandsylvia.co.uk/tech%20 ... charge.htm" onclick="window.open(this.href);return false;

I was doing another 80/90 members split charge circuit today and discovered it had no earth for primary circuit on relay - ie no terminal 85 wire so naturally wasn't kicking in even with trigger wire connected. Took ages to find though!

Relays can be a bit of a mystery for anyone unfamiliar with electrics but actually, they're very simple. I've just done a simple diagram (below) of the relay to show what the relay does and how it all works. Basically the relay a small switch (86/85), switching a bigger one (30/87) but the two circuits not electrically connected. Once 86/85 go live, the switch at top pulls down, allowing power to flow through 30/87.

Second diagram (5 pin relay) shows 87a and how it is live when the alternator is not charging (ie power from a solar panel).

There are all kinds of relays but essentially this is what it does. Higher rated relays have better contacts for 30/87 - simples.



Headlamp relays? They use the original power cable that goes to bulb to energise 86/85 instead whilst a new heavier gauge wire is used for headlight via 30/87. That means the headlight switch no longer carries heavy current with potential for burnt contacts and headlights get a much better route to the power source.

The solenoid on the starter is also a relay. Without it you'd need a giant buzz bar on the dash to start the camper. Modern cars may have many such relays and when you add new accessories (say a powerful horn) you'll need another relay.

[Hacksawbob]

Thanks mr Kid I get the workings of a relay, just what is making my leisure kick in before the engine is turning, I need to find the other end of the blue wire how does one go about tracing a wire from front to back? A long wire on the continuity meter?

[CovKid]

You could try disconnecting the piggyback blue and temporarily running a cable direct to said terminal on alternator. Only reason I mention this is because I had no end of probs splicing into same cable further up the line but if I went direct (which it still is now) I had no probs at all.

Sounds more like the trigger wire is just getting its voltage from the ignition or something. Could be an alternator/diode pack fault but try a direct wire to rule that out - saves tracing the original too.

Wasn't directing the relay explanation at you in particular Bob, just posted it as a general 'how it works' thang. WIKI'd too now.

[Hacksawbob]

Would anyone know where these Westy wires go? The German is for "Control panel", but it isn't the camping one above the sink. The centre blue wire is going to the back of the alternator as the engine running signal. The left hand one is the chunky red one that goes back to the driving battery, but the other one is the small 86 red black trigger wire, I dont think this goes to earthit heads on up to the dash direction I think. I was wondering if the numbers relate to the bently diagrams? and what doe Kl mean? I really need to trace this red black wire.

[California Dreamin]

Thats the split charge relay so 30 (terminal 87 on the relay) goes to the leisure positive + terminal to charge when the engine is running.
61 & 50 (terminals 85 & 86 on the relay) are the blue alternator switch wire and earth (the switching side of the relay).

But you must know this as you have just been replacing yours?

Or am I going bonkers...lol

Martin

[Hacksawbob]

I dont think that it just goes straight to earth thoough I think it goes somewhere else first, I mean there is a good earth right there in the battery box! not even VW with their idiosyncratic wiring would send that red black wire back into the loom when the is a good earth not 5 inches away!
and red black for an earth? surely not?

[Oldiebut goodie]

Well the EC (Germany and France mainly) decided to change the colour of the red live in mains wiring to the brown that is more visually an earth colour (and a lot of vehicles wiring was a brown earth also) - idjits! what more can you expect.

[CovKid]

I happened to work on Ronsrecord's Joker in recent weeks and this too had a small red/black wire attached to the earth terminal on split charge. It failed to make the circuit though and rather than face stripping out entire units from the inside, I opted to cut this off and simply made a fresh earth to nearest point. Worked fine then. Took some time to isolate the problem though.

If you have any luck tracing the small red/black then I'd be interested to hear where but as said, the nearest earthing point makes better sense. I can't see where else that small wire could go other than earth since thats the role of that particular terminal. Just ground the relay and it should work fine.

[Hacksawbob]

I see your point The crown of earths behind the dash is best best, it might be one of them that to plug in the loom at the factory was more time economical than to connect earths in the battery tray even if it used more wire....

[Hacksawbob]

Or just thinking (bad idea I know!) if the blue alt wire has been hijacked for leisure battery and fridge stuff ... how does the "battery charging" light on the dash work, could it be this red black that goes to the dash to perform this function? surely you would have spotted this though Ralph if you went straight to earth the no charge battery would be lighting on the dash (if it was working?)

[Hacksawbob]

looking at the wiring diagrams red black is the colour the W alternator connection uses that goes to the dash for rev counter duties on the diesel (I think petrol is different?) I'll have a root about tonight and see whats what. probably unconnected to the starting issue but its bugging me now!

[CovKid]

Bugged me too. Yes ignition light on dash goes out as normal so its not that. Besides even VW would have ground that particular circuit at dash end. Send a mouse down there Bob, see where it goes