I wonder if Briskodia can assist me please, I know there are a few threads already on this faut but have checked the wires under the n/s front and they appear to be intact. My questions are related around these wires as when I measure the plug (unplugged)  that goes into the alternator I saw around 13 v on one and 12 v on the other .  I did attempt to run a continuity test from this alternator plug down to the connection on the gearbox and it seemed to be open circuit but I was not sure I was looking at the right connector for the alternator plug , then the heavens opened and I had to cease my investigation.

 

I only realised my battery indicator had stopped working yesterday after I stopped after a 10mile trip to pick up something and returning to the car tha battery was flat! I think its possibe to test the operation of the battery indicator by shorting one of the wires from the alternator connector to ground but have not tried that yet.

 

The only other issue I am aware of on my car that I thought was not related is that when replacing my radiator one of the wires that went to the temp sensor , sheared off. As I did not have any connectors at the time I thought to test it anyway and noticed that the temp gauge was not affected (2 temp sensors maybe) hence have not rectified the issue , could this fault be related do you think?

 

If anyone can add anything it would be greatly appreciated but I did have the battery tray out and could not find a break in the wiring other then the temp sensor already mentioned, the engine seemed to be uncharecteristically oily at the front , no oil leaks but black and mucky hence have spayed some engine cleaner down there and hope to have a betterr look tmrw.

Radiator thermoswitch wire problem won't be related to the battery light not working,  At this time of year the rad fan probably wouldn't see much action anyway even if all the wiring was intact, but I'd fix it before you forget about it, or at least put a calendar reminder in your phone to fix in when the weather warms up a bit.

 

Not sure on the battery light thing.  I'd expect the presence of voltage on the pin that the blue wire goes to to be evidence that the wire was intact.

Tthe wire colours should help to identify the right connector pair at the gearbox bracket: alternator side will be same as at alternator plug, other side the brown or brown/red will change to a lilac/green I think, and the blue carry on through as blue.  If you add the year of your car to your profile I can look up the precise details of the wire colours.

Much appreciated Wino, did not think about the fan cut in switch , ok will put it on thelist. 

 

Should have added that when starting from cold and idling, battery reads 11.8v a smidge of throttle <1500rpm and the battery is reading 14.8v. Just went out and shorted the wires in the alt to ground and no battery light came on the dash! Does that indicate a poss  prob with the dash light and possibly the alternator field circuit ?

 

Car is 05 VRS Fabia with AC

Not sure what your shorting test shows 'cos I haven't tried it myself but I'd guess that it means the blue wire isn't fully intact, as does the rev-related alternator start-up. 

Have another look at the gearbox bracket connection tomorrow if weather and other factors permit.

 

For your car, pin 2 of the alternator connector has a brown/red wire as far as the gearbox connector pair, where it changes to a lilac/green on its way to engine ECU pin 38.

The blue wire (the critical one for battery light function and alternator start-up) stays blue all the way through that connection, and the one at the firewall, to destination/origin at pin 9 of connector XS4 of the Onboard Supply Control Unit in the cabin, above the accelerator pedal.

Edited 26 January, 20197 yr by Wino

Thanks for your wisdom wino, did not have any spare time to investigate further today but will have a look next weekend no.Just returned from a twenty mile round trip in the dark so alternator is charging , just got to remember to rev her more as I usually ridr the torque curve:) still love the car even though she demands more attention from me.

 

A quick question about the alternator , is it worth doing any mainentainance on this , I'm wondering if you can open up the black cover and clean the brushes or get air hose in there in case it aint producing enough omph on th L terminal Fieldcircuit?

 

Still wondering about the measurements on the alt plug when disconnected , the voltage must be coming from somethig else as I thought the one wire was menat to get 12v from the alt itself?

 

Hey Wino, i found the blue wire broken today just as you stated.Down at the bottom  of the n/s front bumper cable was  broken just where it goes into the black plug, not had a chance to repair it but will plan it in for next weekend.

 

Th plug I had been checking was of course the wrong one , whats the best methof of attack , from the top with the battery tray out or from the bottom with the car jacked up ?

 

Thks once again

12 hours ago, cello said:

whats the best methof of attack , from the top with the battery tray out or from the bottom with the car jacked up ?

 

If you've got the gear to get it up in the air safely, access is going to be easier from below.