C max 1.8 petrol 2004 battery light coming on - johnkent

Hello

The battery light on my c max comes up after 30 seconds of starting up

The alternator is charging 14.1 volts with everything on so presume the smart charge is ok

New battery on it so batterys ok

New aux belt so not slipping

Can anyone suggest what else it might be

Thanks

C max 1.8 petrol 2004 battery light coming on - elekie&a/c doctor

If the battery warning light comes on after 30 secs,then the system is charging in default mode,and thus the smart charge system is not working correctly.This could be an alternator or wiring fault.There is a procedure for checking the system properly.

C max 1.8 petrol 2004 battery light coming on - johnkent

Thanks for your reply

Can you link or go through the procedure so i could check it

cheers

C max 1.8 petrol 2004 battery light coming on - elekie&a/c doctor

Hopefully the new battery is the correct calcium type,otherwise the smart charge system will not perform correctly as voltages can peak at around 15.8 volts.If you have a digi voltmeter,then you need to check the voltage at the battery and at the large terminal on the back of the alternator.These should be approx the same.Next,disconnect the 3 pin connector at the alternator.and check voltage on the red/orange lead .Again ,this should be the same as the battery voltage.Do this test engine off. now you need to load test this small red wire with a 21 watt bulb to see if it lights up.If the tests prove good so far,then i would say the alternator is in trouble.It is possible to test the other 2 wires in the plug(blue and gray)but you will need an oscilloscope.Finally,you need to remember that the red battery charge warning light is not connected to the alternator.

C max 1.8 petrol 2004 battery light coming on - johnkent

Thanks for that mate

Is there a fuse in the engine fuse box that controld the smart charge ?

Also the battery warning light still came up after i'd unplugged the 3 pin wire connector is this right.

And worse case how involved is it to get the alternator out in case i take it somewhere to be tested

Cheers

C max 1.8 petrol 2004 battery light coming on - johnkent

just stripped alot of the alternator 3 pin loom out

Found that the blue wire connecting to the plug looks a bit dodgy not broken but is twisted and stretched could be why the battery lights coming on 30 seconds after start up

Can you buy this part of the loom seperate or even the plug and re solder the wires back up

Any help here would be appreciated

thanks

 

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