Hi all. I've a 2002 s type 2.5 se v6 petrol automatic. A couple of days ago,before going out for a drive,i wanted to do the usual under bonnet fluid checks,oil,brake fluid,water etc. After checking all these,i shut the bonnet and went in to have a cuppa,before heading out. With the car being on drive,and in view,i left it unlocked and alarm not activated. Just as I'd finished cuppa,the horn started tooting itself,as if the alarm was triggered. Rushed outside,with keys. The indicators weren't flashing,like it should if the alarm was going off. Tried pressing both lock and unlock buttons on key fob,which didn't help. I then put key in ignition,and that didn't help. I then started the car,and still didn't change. Horn still tooting. Lifted bonnet,and it was still tooting. Then all of a sudden,it stopped. But not for long. It started again,but intermittently. Couple of normal toots,then a more quick and shorter toot. The only thing i could do to stop the embarrassment,was take out the fuse. A friend of mine,who owns a land rover,advised me,just to rule 1 thing out,was to spray WD40 in and around the 2 locking mechanisms were the bonnet shuts down and locks into. Done that,and left it overnight. Put the fuse back in next day,and within 5 minutes,the horn tooted. Just the once,and stopped. But about half hour later,it tooted once again. So i removed the fuse,in fear it would start going off like crazy,as it did in the beginning. With fuse took out,the car was still locking as normal,and the red light on dashboard is flashing. So I'm presuming the alarm is enabled. And there's been no random flashing of indicators,pointing toward alarm being activated. A family member came and tested my battery. It's only 1 of those cheap testers you get,but can tell you how many volts in battery. Reading's were-11:5 with engine off. And 12:45 with engine on. My mechanic said them are low readings,and asked me to take car to him Monday,to test battery on his tester. Which apparently tests the cells in battery,and whether it's serviceable. The battery is 4 years old. I read somewhere,that if you get a gremlin in your car,and it's electrical,1st thing to look at is the battery. Really sorry for this being so long winded,I'm brand new to this. All advice and opinions will be greatly appreciated,thankyou

 

Yeah, that's WAY low. The issue may not be the battery itself. Sounds like your charging system is not properly charging, and thus the battery is getting run down. With the engine running on a '99-'02 model, you should be seeing about 13.7 volts.

The battery itself could be bad, so further testing is required. If the battery is bad, a perfectly good charging system cannot build up proper voltage. Think of it like trying to inflate a balloon with a hole in it.


Maybe that was me. I'm always blathering about the importance of making sure the battery is fully charged battery beginning any electrical troubleshooting. Another rule of thumb is to take care of any known issues (low charging voltage) before digging deeper elsewhere, so it sounds like you're on the right track.

Keep us posted.

 

Thankyou for your advice and opinion,greatly appreciated. When you say "charging system", do you mean the alternator? As my family member who put the tester on battery,told me to start the car mainly to check if the alternator was working. And when the reading went up slightly,he said yeah,the alternator is working OK.
Also,don't know if this would make any difference,but due to ill health,i only use my car like once a week,or sometimes it might be 2 weeks. The usual run i take it on,is approx 30 miles. I'd took it on that run on Wednesday,and he'd done those tests yesterday (Friday) so it was just parked on drive for 48 hours between 30 mile run,and battery test. I would of thought that if my battery was good,then a run of that many miles would be enough to recharge any drop in battery? But as said,my mechanic is testing battery on Monday with his tester,to get full picture of state of battery. But your opinion on what I've added would be greatly appreciated,thanks

 

Not just the alternator. The alternator is the main component, but the complete system also includes the stout wiring that carries the heavy current, ground cables for the battery and engine, the light wiring of the control system, fuses, the drive belt, and the battery to some extent. A fault anywhere, possibly more than just one, can cause the low voltage you are seeing. For example, the problem could be as simple as a loose or glazed drive belt, keeping the alternator from spinning at full speed. Your mechanic should be able to isolate the fault(s) with some basic troubleshooting. None of what you have described sounds like a serious problem, so don't panic.


Not quite. The alternator is responding to some extent so that's encouraging, but everything is not 100%. Hopefully your mechanic will charge the battery, give it a good test, and proceed from there. Testing a battery is more than taking a simple voltage reading at rest. Most likely he will have a tester that deliberately stresses the battery to see how it responds under load, when it really matters.

Not always, especially if the battery was significantly run down before this latest drive. That's why I keep droning on and on about always fully charging the battery before any electrical troubleshooting. If not, you can falsely condemn good parts.

If your mechanic doesn't find glaring problem other than the low battery charge, ask about residual drains on the battery. When the car is parked, various modules stay powered up for about 40 minutes and then go into a power-saving sleep mode. If a module stays awake, or some other similar drain exists, a perfectly good battery will slowly run down. Your mechanic should know how to test for this, but make sure he knows about the 40 minutes (approximately) before sleep mode.

Once you get this present issue sorted out, you may want to consider a battery tender if the car is not driven frequently. Don't get a basic trickle charger, as they simply put out a fixed charge and can cook a battery. A proper battery tender (aka maintainer) monitors the battery and applies a light charge as needed without overcharging. I have a couple of collector cars that I keep on maintainers and the batteries are always topped off and ready to go.

 

Quality advice,thankyou. I'll be sure to mention the advice you've given me to my mechanic. Thankyou for your time,it's much appreciated,and i will update you on how i get on. Thanks again,and take care

 

Take a look at the battery terminal connections and make sure they’re tight and not full of corrosion. A loose battery terminal can result in a low charging battery. Also if somebody replace the battery cable terminals with those aftermarket ones see if the wires loosened up or if there’s rust or corrosion between the wire and the terminals because it’s a common problem with you cause a low charging battery. Finally make sure you have enough water in your battery if not refill it with distilled water and not tap water

 

Thankyou for your advice,it's greatly appreciated

 

Hi kr98664,hope you are well? I must apologise,as in my initial post i made a mistake,about the battery voltage readings my family member done for me. I seen him today,and on reading to him what I'd posted,and your reply,he told me I'd made a mistake,so I'm sorry. I suppose it was an easy mistake to make,but non the less,my bad. Anyhow,the 1st battery reading was correct 11:5 (engine not running) 2nd reading 14:4 (engine running) 3rd reading (engine turned off again) 12:45. I'd misunderstood him,so I'm sorry about that. We had the engine running only a matter of a couple of minutes,and he said it shows the alternator has put a small bit of charge back into battery,just in that short time. He's of the opinion that my alternator is OK,and he reckons the battery is OK too. He's quite knowledgeable on stuff,but no expert,and was limited to using only a small cheap voltage reader. So I'm still popping it down to my mechanic tomorrow,so he can put his reader on it,and see how we go from there. But i felt i just had to get back to you,to let you know about the mistake I'd made,in missing out 1 of the readings. Thankyou for your time,appreciated

 

There’s much better ratings except for the 12.45.. thats a little low. should be about 12.7 V. So it needs to be charged up more/ longer and see if it holds that voltage. But 14.4 is where it should be for charging on the alternator

 

I've heard of this happening, but am not familiar with this personally.

Your revised readings sound much better, although the last reading at rest still sounds a bit low. However, i must caution you how it's easy to get steered wrong by unloaded battery voltage readings. A good battery can falsely indicate bad and visa versa.

I'm very interested to hear what your mechanic finds. Your charging system seems to be working. Healthwise, I suspect your battery is midlife, perhaps not quite yet walking towards the light. But the state-of-charge (separate from overall health, even though somewhat connected) has been on the low side for some time due to the usage pattern of infrequent trips, typically with high electrical loads. A low charge can aggravate the overall health, kinda like when I roust Grandma out of bed at 4am and make her go rollerskating.

Keep us posted.

 

I got in car this morning,to take it to my mechanic,to test the battery. Only to turn the key to ignition lights on,and got all the messages you get when your battery is goosed. DSC NOT AVAILABLE,PARKBRAKE FAULT,ABS FAULT, etc. I knew straight away what this meant,as it happened 4-5 years ago,when had to get new battery. I still give it a go,but it didn't even turn the crank an inch. Rang my mechanic,who's a very busy guy (what good mechanic ain't) and he's ordered me a new battery,and is coming out in morning,when he can fit me in between other jobs,to fit it. And he's also going to do checks,1 being something I've not heard of before. A parasitic draw test,to see if there's anything that's not turning off,module etc. So maybe,just maybe,the matter of my horn tooting randomly all of a sudden,was a kinda warning sign? Anyhow,everything crossed,that all reads OK tomorrow,and it was down to end of life battery. And yeah,i think I'm definitely going to have to start giving the car more runs than i have been. I'd like to thank you all again for your much appreciated advice,and I'll most definitely keep you updated on things,thankyou

 

Hi folks,update. my mechanic came out to me earlier today,to fit new battery,and put his tester on,to run all the tests needed. Obviously with it being brand new,all the voltage tests were great. Alternator test great too. He also ran the parasitic draw test,to see if anything was drawing energy from the battery,and there was nothing,all good. He then tested my old battery,and it showed that 1 of the cells in it had shorted. We then reset everything that needed to be reset after having new battery fitted. Parkbrake,anti trap function on windows and radio etc. I then took car for a decent run,to reset the DSC (dynamic stability control) which needs at least 10 miles to reset it. When back,i put the fuse for the horn back in. And no random tooting. But i only left it in for 4 hours,and took it out again,just for the night. It's evening time here now,and i don't want to disturb people who've just got in from work,or even worse,in the middle of the night,just incase it happens to start tooting randomly again. Yep,it's got me paranoid ha ha. But i just wanna be sure. So soon as I'm up in morning,and the neighbours are,I'll put the fuse back in,and leave it in all day,and hopefully all will be good,and my car can hand me back my confidence. Again,I'd like to thankyou for all your advice,and also the questions i needed to ask my mechanic. I've certainly learnt from this. Everyday is a school day hey,cheers folks

 

On this site look up quiescent current

- how to test, what it should be, etc

If you have a problem it will just be a matter of time so test now before it ruins the new battery.

 

If you still have an issue with your horn be sure to take a look at the seteering wheel switch. Sometimes these get corroded and can occasionally 'stick" Does it "toot" when you press the steering wheel? Also, and I am uncertain, do these cars have a horn relay? Those can go bad sometimes too

 

thankyou for the advice on this,greatly appreciated

 

it's been a few days now,since new battery fitted,and horn fuse put back in,and no random tooting of horn at all. Yea,it toots when pushing the steering wheel. When the problem 1st occurred,that was 1 of the 1st things i did,just to see what happened,and it worked OK from steering wheel. And also,like you say,to see if it was maybe sticking. But the horn was just randomly tooting of it's own accord. Yes,they do have a relay,which is situated in the same fuse box as the horn fuse,under the bonnet. When my mechanic tested my old battery,and found that 1 of the cells had shorted,he told me of the different things he's witnessed over time on others vehicles,when the culprit was a failing battery. Lights randomly coming on,or indicators flashing,and even windscreen wipers operating. Judging by how fast my engine turns over now,with new battery on,i can say,that my old battery must of been poor for a long time,just by comparing how the engine used to turn over,to now.
thankyou for your advice,as with all others,it's greatly appreciated.

 

[QUOTE=kr98664;2613391]Not just the alternator. The alternator is the main component, but the complete system also includes the stout wiring that carries the heavy current, ground cables for the battery and engine, the light wiring of the control system, fuses, the drive belt, and the battery to some extent. A fault anywhere, possibly more than just one, can cause the low voltage you are seeing. For example, the problem could be as simple as a loose or glazed drive belt, keeping the alternator from spinning at full speed. Your mechanic should be able to isolate the fault(s) with some basic troubleshooting. None of what you have described sounds like a serious problem, so don't panic.




Not quite. The alternator is responding to some extent so that's encouraging, but everything is not 100%. Hopefully your mechanic will charge the battery, give it a good test, and proceed from there. Testing a battery is more than taking a simple voltage reading at rest. Most likely he will have a tester that deliberately stresses the battery to see how it responds under load, when it really matters.



Not always, especially if the battery was significantly run down before this latest drive. That's why I keep droning on and on about always fully charging the battery before any electrical troubleshooting. If not, you can falsely condemn good parts.

If your mechanic doesn't find glaring problem other than the low battery charge, ask about residual drains on the battery. When the car is parked, various modules stay powered up for about 40 minutes and then go into a power-saving sleep mode. If a module stays awake, or some other similar drain exists, a perfectly good battery will slowly run down. Your mechanic should know how to test for this, but make sure he knows about the 40 minutes (approximately) before sleep mode.

Hi,hope you are all well. Firstly,a week on from having new battery fitted,still no random tooting of horn. So it seems it was the old battery failing was the cause. Regarding the advice on getting a battery tender,with me only using my car once a week,or sometimes once a fortnight,due to ill health,to keep my battery topped up. It would be a real struggle for me to keep taking off the battery to put it with the tender. So would it be any good,say at least once a week,in between me taking car out for drive,to start it up on drive,and leave the engine run for say half hour? With radio and heater blowers off etc. Would that keep battery topped up at all? Thanks,kind regards

 

I never remove or even disconnect my battery when I put it on a battery tender I just took the battery tender right up with the battery still mounted in its regular configuration and disconnected when I go to drive it, so I don’t see a problem with leaving it connected

 

Oh OK. Maybe I've got the wrong idea. I just imagined a battery tender was like a charger,as in when your battery is flat,ya take ya battery off car,and charge it in house maybe overnight. Do these battery tenders still have to be plugged in to the mains? Or are they a charged up power source in themselves?

 

plugged into the mains.