Electrics problem I think!

[121Dawn]

Hi I have a new to me focus 1.8tdci. I haven't used it for about 4 days but when I put the key in the ignition it was like all the lights were on fully charged and at full brightness but it wouldn't turn over it wouldn't even try. Instead every light on the dash went out and the armed light was flashing as though I'd armed it with the remote. Any ideas. Oh and the battery light was on but the battery was brand new last year. I have left it for day before without starting it and have never had a problem.

[k_j_jacobs]

do you have access to a multimeter?

 

Put a test on the battery and see what the voltage is reading. it should be about 12v if its any lower

then it probably will not be enough to turn over the engine. You will still get lights on in the interior but not enough to fire up the starter motor

[Dee_82]

its not so much about voltage, its current that is the important bit, referred to as Amps

if the battery has 12v on it those LEDs and bulbs might all be good, but if the batter is old then its CCA (cold cranking amps) might be seriously diminished.

Volts is a good indicator of a nackard battery but its only a small part of the story and it might lead you down the road if you rely solely on it. 

for example, my car will turn over quite happily with 11V which is what it is at in the mornings, no hesitation, first time it starts no matter how cold it is

However not that long ago I was having issues where it was showing 12.3v on the terminals but refused to turn over, volts were good, but it wasn't holding a change, the battery was a gonna.

If you can, take that battery to a garage or Halfords, they can load test it and see if its any good or not. whilst a volt meter can be useful, its not going to tell the full story and may even lead you to assume the battery is good if its showing 12v

in saying all that it might not be battery related at all however its the quickest and easiest thing to check and wont cost you a penny.

whilst your at it, check and clean the terminals on the battery. when you know the power is good, you can move on to other things, possibly the IC would be my next thought

 

[k_j_jacobs]

first steps first before disconnecting the battery is to establish where we are at tho is the battery drained? if not then we should trace it back further.

 

 

http://www.aa1car.com/library/voltage_drop_testing.htm

[mjt]

7 hours ago, 121Dawn said:

I haven't used it for about 4 days but when I put the key in the ignition it was like all the lights were on fully charged and at full brightness but it wouldn't turn over it wouldn't even try. Instead every light on the dash went out

That means the battery is seriously discharged. As Kevin & Darren said above if the battery is low on charge it can still activate the dash lights but the votage will collapse when the load of the starter is put on it. I'd try putting it on charge, for 24 hours if possible.

While the car has beein sitting unused there will still be a small current drain from the battery powering the alarm and keeping the radio and ECU learned settings etc. That should not affect a healthy battery over a four-day period. There have been instances where the dash power has stayed on. It should power down after a set time after the ignition is switched off but some owners have reported failure to do this. Once you're up and running that is something to check.

The capacity of batteries can be seriously weakened if they are heavily discharged. They don't fully recover, although some chargers claim to be able to recondition a badly-discharged battery.