Auto electrics issue

[FunkyCatUK]

Dear all,

Just wondered if anyone could solve this puzzle:

Today I changed the headlight bulb on my car. It all worked fine when fitted, but then -

• When I took the ignition key out I noticed the headlights stayed on (I've had the car 10 years - they only work with the ignition key in).
• I then tried to start the car and there was absolutely no cranking from the battery at all.
• Checked the voltage and it showed 12.6v or thereabouts.
• Tried to start again and no joy.
• Noticed that the voltage dropped to 8.5 on turning the ignition key on, but absolutely no sign of the car trying to start at all.
• Tried to turn on the headlights and the main beam (the bulb I changed on one side) were dead on BOTH sides of the car!
• Key fob operated locking also seem dead (but battery shows back to 12v).
• Checked if I broke, disconnected any wires on the headlight cluster but they seem to be ok.
• Lighting and ignition fuses are both ok.

Not sure if any members would have any idea what the problem was.

Thank in advance

 

[Richard-the-Ninth]

What happens if you take this new headlamp out?

 

[Geoff1946]

What are you testing the battery with and how ? If you are using a common multimeter, testing with no load is meaningless. If it drops to 8 on load then it's dead, probably permanently.
Guessing, it sounds to me that your battery has/had very limited capacity and you used it all testing your new lamps. Subsequent attempts to start the car have finished it off. You might get away with recharging......

 

[ProDave]

Try charging the battery first. And check you did not detach an earth strap somewhere while changing the bulb.

 

[SPECIAL LOCATION]

[*]Noticed that the voltage dropped to 8.5 on turning the ignition key on, but absolutely no sign of the car trying to start at all.

8.5v?
Battery is shot by the sounds of it?
How old is the battery?
Average lifespan for a typical car battery is approx 5 years..

 

[UNG]

Today I changed the headlight bulb on my car. It all worked fine when fitted, but then -

Did the car start ok or was it sluggish turning over

• When I took the ignition key out I noticed the headlights stayed on

Does the car have a timed follow me home function on the lights

• (I've had the car 10 years - they only work with the ignition key in).

So have you had the car from new

• I then tried to start the car and there was absolutely no cranking from the battery at all.
• Checked the voltage and it showed 12.6v or thereabouts.
• Tried to start again and no joy.
• Noticed that the voltage dropped to 8.5 on turning the ignition key on, but absolutely no sign of the car trying to start at all.
• Tried to turn on the headlights and the main beam (the bulb I changed on one side) were dead on BOTH sides of the car!
• Key fob operated locking also seem dead (but battery shows back to 12v).
• Checked if I broke, disconnected any wires on the headlight cluster but they seem to be ok.
• Lighting and ignition fuses are both ok.

All the above suggest a battery issue, how old is the battery on the vehicle while they can appear ok they can cause so many issues, with vehicles these days being extremely power hungry if the ECU's are not seeing the expected readings from powered sensors you can get a lot of cascade faults across the ECU's

From past experience with a number of vehicles without connecting a diagnostic tool and reading the DTC codes you are on a hiding to nothing IMO and just clutching at straws trying to repair it. At least with a diagnostic tool you can read and save the codes before erasing / resetting them

 

[UNG]

For checking the battery health I use one of these Foxwell BT100 it is a good reasonably priced battery checker that is handy to have in the toolbox

 

[FunkyCatUK]

Many thanks, all.

Did a jump lead start with a neighbour's car today and it started straight away. Battery was at 14.something v when running. Will go for new battery tomorrow (bearing in mind the immediate start from donor battery and what's been said above). Was weird, though, that it just came out of the blue immediately after putting that new bulb in! Detached earth strap is interesting - not sure where to look for that in relation to the headlights and what I might have damaged/disconnected whilst changing the bulb.

Interestingly, whilst it was running today (after donor battery starting), the 'ESP OFF' light was illuminated all the time on the dashboard. This normally comes on when turning the ignition key, but then usually goes off after the car starts. Pushing the On/Off button for this made no difference. Had read elsewhere this occurs when the battery has been disconnected but should go off again after a short time (which it didn't). Hopefully all will be fine and dandy with a new battery

Thanks, again.

 

[mainline]

Many thanks, all.

Did a jump lead start with a neighbour's car today and it started straight away. Battery was at 14.something v when running. Will go for new battery tomorrow (bearing in mind the immediate start from donor battery and what's been said above). Was weird, though, that it just came out of the blue immediately after putting that new bulb in! Detached earth strap is interesting - not sure where to look for that in relation to the headlights and what I might have damaged/disconnected whilst changing the bulb.

Interestingly, whilst it was running today (after donor battery starting), the 'ESP OFF' light was illuminated all the time on the dashboard. This normally comes on when turning the ignition key, but then usually goes off after the car starts. Pushing the On/Off button for this made no difference. Had read elsewhere this occurs when the battery has been disconnected but should go off again after a short time (which it didn't). Hopefully all will be fine and dandy with a new battery

Thanks, again.

Modern ecus can be damaged by jump-starting.

When you change for a new battery, leave it completely disconnected for a while before replacing with the new one.
Also make sure the ignition is off etc.

 

[UNG]

Modern ecus can be damaged by jump-starting.

Usually when connecting / disconnecting the cables

Also make sure the ignition is off etc.

Some vehicles also need time to go into sleep mode after switching the ignition off

When you change for a new battery, leave it completely disconnected for a while before replacing with the new one.

If the vehicle has an inteligent / active charge system which changes the charging profile as the battery ages you often have to reset it with a diagnostic tool
Quite often on newer vehicles when the battery fails it can cause the alternator to subsequently fail, I have seen it were the alternator fails after a new battery is fitted and it kills the new battery as well

 

[FunkyCatUK]

Thanks.

Car is 2010 Hyundai i30, so pretty old and basic.

Fingers crossed.

Cheers!

 

[mainline]

Thanks.

Car is 2010 Hyundai i30, so pretty old and basic.

Fingers crossed.

Cheers!

Your car will most definitely have smart charging.