Horn problems

Hi All,
A local guy has dropped his RR in for me to have a look at battery drain issues he is having.
He bought it from new and it has now done a massive 28,700 or so miles in it's 11 year life,never scraped bashed or been offroad.
But still has issues which i suppose are p38 and time related.
Battery is draining over a couple of nights, i have already disconnected blue rf wire at unit,no joy.
Was told today when he dropped it off that the horn started going while driving the other day and the fuse was removed ???
I am thinking fuse box possibly,time for a sniff test methinks
Pics of the car . Immaculate vehicle in and out

Also look for wet carpet in the drivers footwell. If the RF receiver fails, disconnecting the blue wire will not stop it cycling the locks and draining the battery.

Datatek said:

Also look for wet carpet in the drivers footwell. If the RF receiver fails, disconnecting the blue wire will not stop it cycling the locks and draining the battery.

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Thanks Keith, i am just about to give it the once over.
Just put the mm on to check charging rate at battery and only 13.5v @ 2000rpm with lights on,wondering if the alt might be the culprit,draining the battery when switched off?

rodntod said:

Thanks Keith, i am just about to give it the once over.
Just put the mm on to check charging rate at battery and only 13.5v @ 2000rpm with lights on,wondering if the alt might be the culprit,draining the battery when switched off?

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Could easily be the alternator, should have 14.2 volts after a short period. Could also be the battery.

Datatek said:

Could easily be the alternator, should have 14.2 volts after a short period. Could also be the battery.

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Brand new batt just fitted and checked today .
Put nano on it and is showing a short circuit in right blend motor, but should not affect battery when car is off and key removed,should it??

rodntod said:

Brand new batt just fitted and checked today .
Put nano on it and is showing a short circuit in right blend motor, but should not affect battery when car is off and key removed,should it??

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I have one of those does not effect battery. New blend motors waiting better weather. Why could it not have been her bloody side? Freezing me nuts off and she is toasty warm. No flaming justice.

wammers said:

No flaming justice.

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I think Gems mite disagree :behindsofa:

wammers said:

I have one of those does not effect battery. New blend motors waiting better weather. Why could it not have been her bloody side? Freezing me nuts off and she is toasty warm. No flaming justice.

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I know,thank god my old diesel is still toasty inside. Cheers for the info Tony,i have a feeling with the horn issue it may be fuse box or BECM related.
Just found out that no response from car when fob depressed although car starts fine with no messages and fob flashes?
I think it may be time to get the unlock codes for the v8 for my nano and go right in to the system and see what we find.
Cheers so far guys
Ed

rodntod said:

I know,thank god my old diesel is still toasty inside. Cheers for the info Tony,i have a feeling with the horn issue it may be fuse box or BECM related.
Just found out that no response from car when fob depressed although car starts fine with no messages and fob flashes?
I think it may be time to get the unlock codes for the v8 for my nano and go right in to the system and see what we find.
Cheers so far guys
Ed

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Pretty simple circuit. Horn push -> rotory coupler -> relay 9 fed by fuse 41.

Take the blue pill..

Update;
Dirty conn at back of alt,cleaned up and now have 14.4v at battery.
BECM is still not going to sleep on it's own. Can get it to sleep pulling certain fuses and the voltage at battery stabilizes and tell tale light on console will go out.
The only thing is, if you restart the car and leave the fuse out(diag or fan ) the car will not go to sleep when switched off,until you pull other fuses.
Once car is asleep and all the fan ,air con,horn and diagnostic fuses are out,start it again and switch off and still won't go to sleep.
Any ideas guys??

Check for corrosion in the OBD socket, otherwise I'd be looking at the fuse box.

Datatek said:

Check for corrosion in the OBD socket, otherwise I'd be looking at the fuse box.

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Cheers Keith, fuse box out time

The Mad Hat Man said:

I think Gems mite disagree :behindsofa:

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Naaa just a bad tempered old git. Got up and couldn't find his slippers possibly.

Battery drain, Horn going off while driving.... Something i've seen many times.

These faults could be caused by the becm.

When you start to pull your hair out, give me a shout & I'll test your becm out for you.
All you have to pay is the postage as we test for free.

Rick-the-Pick said:

Battery drain, Horn going off while driving.... Something i've seen many times.

These faults could be caused by the becm.

When you start to pull your hair out, give me a shout & I'll test your becm out for you.
All you have to pay is the postage as we test for free.

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Cheers Rick,hopefully won't need your services mate, but really appreciate the offer.
However, watch this space.

Latest;
I have finally got her off to sleep
After removing and checking fuse box-like brand new -removed all fuses and relays, all like new,no smells or signs of heat anywhere, all under bonnet earths etc, put it all back together and noticed that when i remove the 5amp diagnostic fuse, i get a single chirp from the alarm
Car also has a non standard pair of front spots on front bumper, wired from battery ,through relay,so disconnected them.

I have started her up and switched her off 3 or 4 times since then and she is going to sleep somewhere between 5 and 10 mins later.

I think we are on the right track, next stop, obd socket.

Cheers so far guys, appreciated as always.

Rick: i think the owner has been confusing the alarm for the horn ,but will check with them.
Keith:i think you were spot on with the OBD socket,judging by how wet the passenger floor is

Just to eliminate all possibilities. The alternator isn't starting to leak back is it?

J

Should have read further! Looks like after-market bodge!

If i leave the 5amp diagnostic fuse out ,the car goes to sleep fine.
but when the car is started and has been running for a minute or 2, you can hear a very short chirp every second or so from the alarm sounder,when you are sitting in the car it sounds like a loud clock ticking,but when you open the door you can hear the origin???

Rick,i might need you after all