Urgetn Help Needed please !!

[rutland-boy]

OK Update.

Not the relay (itself) had it out, brand new, checked it with a 12v regualted supply (I used to be an electronics engineer!!), works fine.

Decided I would 'manually engage the relay' ie get a crock clip and keep the relay contacts together.

Guess what - All normal everythign works fine when I do this.

Even starts like it.....

So question now is :-

How is the relay triggered ? - does its feed come through the infamous 'hazzard switch' - or somewhere else, I have a circuit diagram and its fed on one side by the ignition switch (Which has been replaced to fix the fault!!) but its unclear (to me - thoose diagrams are not great to read if your not an auto tech!).

Any ideas - also if I did this a little more perm is it safe ?

Could it be an earth problem (still?), is it the hazzard switch ? - I could imagine paying for hours of time in the shop and still not finding it

Opinions please ?

At least I have a way of makingn things work now (!) . as I understand it this relay disconnects things which draw high current during startup so full current can be sent to the starter motor, after that it connects everything else. Surely this 'fix' is OK short term, as long as I'm careful whats on when I start it ? perhaps at least until I get a new hazzard swtich

Thanks for all the great help on here.... Really great....

[RichRS6]

Glad You've found a temporary solution to this and its always good to get results so it can be added to the knowledge base !!

It would be a good idea to replace the Hazard switch as it's prone to failure, cheap to buy (£30.00 ish) and easy to replace.

At least then You can rule it out as a cause of Your problems.

Also get the Battery drop tested (Halfords/Krap fit etc will do this for free) as a dead cell can cause all sorts of weird problems especially problems when the Battery is under load..

[batty]

ignition switch, at a guess.
the start position disables power to the rest of the car whilst cranking the engine, via this relay

[bilko1]

ignition switch, at a guess.
the start position disables power to the rest of the car whilst cranking the engine, via this relay

Audi changed the switch for him.

[Shoppinit]

I would wire up 2 LEDs to show me when the relay was being commanded and when it was closing (and also a switch to force the relay to close) so that you can see when the relay is dropping out (and bypass it if necessary with the switch).

It does sound like ignition switch Are you sure they changed it properly?

As far as I can tell, the wire goes more or less directly from the ignition switch to the relay and then from the relay to earth with very little in the way of terminals / connectors in between. You could always try wiring the ignition switch directly to the relay pole with an extra wire (temporarily of course) to see if that improves it. That would eliminate any problems between the switch and the relay. It's the yellow / black wire;

[rutland-boy]

OK Update Round Three !!

Had to go to London for three days, left the RS6 in a secure rail car park, came back last night to discover flat battery !!

So, forcing the relay closed permanently must cause extra drain and flatten the battery

AA Called, of course deadlocks (and for some reason the boot wouldn't open on the key something else to fix !), quite funny dismantling the rear seats and
getting to the battery but he did, and started it - well done AA man.

Drove home, thought I would struggle to start it this morning as lights etc on would not allow battery to charge, but this morning, again flat as a pancake

So seats down battery jumped and started again.

So after allowing a good charge started to look at the problem again.

removed relay, checked for 12V on one side - Yes with ignition on
checked for earth on the other - No

Ahh earth problem ?

Rigged a wire from where the earth should be on the relay to a suitable good earth.

Relay On when turn the ignition switch, off when starting and on when started. As per it should be.

added a switch to the earth line just in case.

Interesting though as I put it together again and discovered that even without the switch and wire it worked fine, left the switch and wire in just in case so I can get everything working if needed.

What seems to be interesting is, that it went fault again (no indicators or wipers etc.) and by simply flicking the switch - IE earth then no earth - everything works again as normal - as if its latching the relay.

Anyway will see how it goes and have ordered a new hazard switch just in case.

Does any part of this area of the circuit go through the Hazard switch ? might be something in there ?

Ideas ?

Thanks for the help / advice.

[spurtle]

Duff battery, like Rich said?

[rutland-boy]

Update....

Been fine, battery fine, have had to use the 'switch' three times, and so far it has worked perfectly each time.

No flat battery, simply worked.

Will order Hazard Switch and replace just in case.....

[Shoppinit]

Random. I'd change the relay again, just in case. See it changed with my own eyes, if you see what i mean

[Ice_Coffee]

I would disconnect the original earth from the relay and compare it's resistance to chasis again your new temporary instalation.
Of course resistance is not the be all and end all, you may have 0Ohms to chasis but can it carry the current, I would also put an ammeter in series on both legs, separately to see how much current is being drawn, ultimately I think the original cabling has a poor termination, further this means it will run hot as you try to draw more current than you need through it, I recommend you leave your switch on whilst it is in use as (depending on the thickness of wire you have used) double your current capacity.

[Ice_Coffee]

that again on the top line should have read against