alternator problems

[scantronic]

always joyous to have car problems

battery light sometimes not illuminating when ignition is turned on as shown in the image below

however it's started to illuminate again
i note the battery light was lit dimly when the engine was running, and now it's lit solid
not charging either, car does not get short journey'd and had done a 80 mile trip the previous day

i've sourced a replacement alternator, but what's the best way to make sure it's that? i checked the voltage on the actual alternator today whilst running (big cable and battery negative) and that was 12.2v so it's not outputting it seems

1993 Citroen XM
2.1 turbo diesel automatic

 

[carmanmemoranda]

Id start by a full charge on the battery and then have it tested.

Once you confirm the battery is ok (or not) then the alternator, or it's wiring looks suspect.

 

[scantronic]

wiring looks fine, from what i can see

everything else works correctly and the battery is relatively new and a good brand

it cranks fine, i suppose it could well be the original alternator.....done well if it is

 

[Burnerman]

I think if you were to dismantle the alternator you'd find that the copper slip rings inside were well worn.......basically if these things are gone then no input current means no output current, if you see what I mean - and failure plays havoc with the dash lamp.
Look for 14.5v when the engine is running and the lights on.
John

 

[scantronic]

headlights are dim and the battery is at 12.1v running so yeah it's not charging

replacement looks awkward, it seems i'll need to take the hydrualic pump off

 

[baldykev]

long shot. Have you removed connector of alternator and checked for corrosion like I said long shot but have had this once

 

[carmanmemoranda]

headlights are dim and the battery is at 12.1v running so yeah it's not charging

replacement looks awkward, it seems i'll need to take the hydrualic pump off

it does sound like alternator. but I would still want to confirm battery is good.

Any excess heat from battery or alternator when engine running?

 

[scantronic]

nope everything is cool, no signs of shorts

i had issues with the cassette radio cutting out whilst indicating the other day, and the wipers going slow so i suspect this explains that

 

[fixitflav]

wiring looks fine, from what i can see

everything else works correctly and the battery is relatively new and a good brand

it cranks fine, i suppose it could well be the original alternator.....done well if it is

My best guess is alternator brushes. Modern alternators are mostly very hard to dismantle, no doubt to discourage DIY repairs, but one from 1993 may not be. If you can get hold of brushes I'd start there. Not expensive so you could buy them on the off-chance before removing the alternator.

 

[scantronic]

just an update, i fitted a replacement alternator (what a job!) but problem is all sorted, charging at a strong 14.8v and all functions working well

 

[norseman]

just an update, i fitted a replacement alternator (what a job!) but problem is all sorted, charging at a strong 14.8v and all functions working well

Well done for keeping a 29 year old motor in use

 

[scantronic]

of course, it's an absolutely lovely car that's been quite reliable and a good bit different to the rest