Alternator light on!

[Nisspatrol]

Hey folks,
went to cruiser park on the weekend, had a ball in the mud BUT!, got myself all muddy and now the alternator light is on and the battery is not charging at all, is this common?, ive cleaned it all up and still have the same prob, also it was loosing all power and stopping completly on the way home, we'd wait 5 mins and start it and we'd be off again, then 10 mins down the road it'd do the same,weird stuff, any ideas how to fault find.....pretty please...
thanks heaps
warren

[muppet_man67]

it could just be a bodgy connection, try cleaning out the plug on the alternator. If you had a multimeter and knew how to use it you could put it on the alternator to check if its the alternatot thats stuffed or a connection somewhere.

[salli]

The alternator brushes would be not free as the mud has caked on them and they are stuck and would not be touching the slip rings.Ive had this happen a number of times ,First of all get the hose and give the alternator a good blast of high pressure water .If that has not fixed it ,u will need to take off the brushand regulator assembly and free it up with some wd spray .Don't know if ur Sierra has a internal or external regulator and brush assembly,but my Jimny has a internal assembly so a bit more work involved.

[Nisspatrol]

thanks heaps fellas, ill give that a go tomorrow after work
thanks again
warren

[Nisspatrol]

unfortunatly didnt work fellas, heres the full story to date PLEASE HELP
i took my 97 coily zook for a swim on the weekend in the mud, on the way home the charge light came on, it disappeared after a while, then it came back on, then off and then on permanantly, drove 150ks home, and i was having problems with keeping it running all the way home, it would all of a sudden conk out, id play with the coil and leads, get back in and it would run fine for about 15-20 mins and then did it again, anyway, it conked out just up the road and the batt was dead, had to push it home, washed all the mud out of the engine bay, gave the alternator a good clean, light still on, check the batt voltage not running 11.5v, voltage running 11.5v, checked voltage with the negative probe on the batt negative and the positive probe on the thick wire coming off the alternator 11.5v, removed the thick wire and checked the alt running with the red on the bolt and the black on the case of the alternator, 13.5v looks good to me?,
i think theres something wrong along the line but im buggared if i know!
can anyone point out were ive gone wrong, or a possible answer to my problem, it would be much apprieciated.
cheers heaps
warren

[muppet_man67]

so is the alternator charging?

[built4thrashing]

time to upgrade to an EF alt. so easy to do if you get one that works

[mr green]

if you have 13.5 v at the alternator there is nothing wrong with it. on my leafy it had a blade type joiner about 6'' from the alt and had a dodgy connection. did exactly what you are saying.

[Nisspatrol]

i think it is charging, when i put the tester on the positive conection on the alt, and negative on casing( both disconected from batt) it reads 13.5v at 2500rpm at the alternator, but the charge is not getting to the battery, what tha????
hope this helps
warren

[Guy]

There is a fuseable link between the the alt and battery ... sounds like yours is blown ..

Pop into a local autoelec and should be able to source another for a couple of $$

[mr green]

there is not much wire between the alt and the battery. start it up and have a good wiggle of the harness and watch your voltmeter on the battery at the same time. did you read my last post, it was put on the same time as yours.

[bazooked]

also dude i posted in the auto sec ur charge rate should be around the 14 mark with the lights on at 2000rpm, u will find the alt is on its way out aswell.

[Nisspatrol]

ok, tested again
battery connected
between pos post on alt and casing of alt, no continuity
between pos batt term and pos post on alt, continuity
between neg batt tern and casing, continuity
pos and neg batt terms off
between pos post on alt and casing of alt, no continuity
between pos batt lead and pos post on alt, continuity
between neg batt lead, veh earth and casing, continuity

heres a funny one
with both leads disconnected, multimeter set to continuity, when i put red multi probe in batt earth lead and black on pos lead, it has continuity, but not vice verca, i thought continuity was just that, continuity, with all other tests it doesnt matter which way round the probes are!
crazy, any more ideas.....please

[Nisspatrol]

Ok fellas,
Alternator all fixed, here's what it was, pulled alternator out and one brush was fine but the other was stuck all the way in, charging fine now.
thanks heaps for all the help. now onto my other problem...........