Alternator charging problems

Hi Guys,

I wonder if someone can assist.

I have an issue with the alternator in my MK1 16v at the moment where it will not charge the battery. I have proved this by putting a mutimeter across it and there is no voltage coming from the alternator at all.

I subsiquently bought another alternator and fitted that with the same result as above.

I have read all the threads regarding the blue wire and the warning LED on the dash and that is my next area of investigation as the dash warning LED does not illuminate at all anymore.

My question is, if it turns out to be the LED where can I get a new one from and how do I fit it into the dash?

Any help would be much appreciated.

Cheers Bob.

start with the blue wire, usually bulb out lasts the car! there should be a single pin connection near the battery +ve. if you earth it the light should come on with the ignition, if it does you know wire is ok back to the fusebox at least. once that checks out trace the wire from spade to the alternator, maybe its got a bad connection on the ring terminal or has snapped somewhere

Thanks for the help mate.

I have been tinkering this morning and have done as said above and this has proved the lamp still works!

I have cleaned all terminals on the blue wire and stripped the black plastic protection to check for breaks and all is ok and double checked continuity with a multimeter.

Still no light on the dash whatsoever!

I am stumped at the moment!

Do you know what inside the alternator controls this little circuit if anything?

maybe try ruinning a fresh wire from the blue spade to the alternator d+?  if it still doesnt work then that would suggest the alternator is stuffed, or maybe its not got a good earth contact. it earths via the block to the gearbox then back to the battery -ve, if the block/alt has been painted then that would stop it working. to rule it out run a jump lead from the battery -ve to the body of the alternator somewhere

Cheers mate, should there be an earth lead from the alternator casing then because I haven't got one!?

no the alternator earths thru the engine, gearbox then finally the battery -ve cable. this is why the battery earth has to be good its for the alternator as well as the starter

Ahh yes of course, starter works ok so there may be a dodgy connection between the alt and block! I think I did paint it when I put it together. I'll try the jump lead trick first to make sure.

Cheers mate appreciate the help.

If you have a test lamp clip it to the battery -ve and with the ignition on put the lamps spike on the alternator casing, make sur you are on the metal on the casing not just paint, if it lights the alternator is not properly earthing to the engine block. Remove alternator and clean mating surfaces between alternator and block/brackets

rubjonny said

maybe try ruinning a fresh wire from the blue spade to the alternator d+?  if it still doesnt work then that would suggest the alternator is stuffed, or maybe its not got a good earth contact. it earths via the block to the gearbox then back to the battery -ve, if the block/alt has been painted then that would stop it working. to rule it out run a jump lead from the battery -ve to the body of the alternator somewhere

Hi John,
I've tried the above the light in the dash works when I earth the block near the battery so i guess as you say the alternator is stuffed.
Could you tell me what size allen key/star bit I need to get the alternator off (the one through the cambelt cover) as I can't find anything to fit in my socket set?

Thanks John.

hmm now you're asking, I cant remember off hand! it may have rounded

before you take the alternator off though, try earthign the blue wire ring terminal as well. if light comes on then yup, duff alternator. if not, the blue wire is snapped somewhere between the battery plug and the ring terminal

if the bolt is rounded it is possible to unbolt the lower bracket from the engine with alternator still attached. dead fiddly but you can do it!

Robbo said

rubjonny said

maybe try ruinning a fresh wire from the blue spade to the alternator d+?  if it still doesnt work then that would suggest the alternator is stuffed, or maybe its not got a good earth contact. it earths via the block to the gearbox then back to the battery -ve, if the block/alt has been painted then that would stop it working. to rule it out run a jump lead from the battery -ve to the body of the alternator somewhere

Hi John,
I've tried the above the light in the dash works when I earth the block near the battery so i guess as you say the alternator is stuffed.
Could you tell me what size allen key/star bit I need to get the alternator off (the one through the cambelt cover) as I can't find anything to fit in my socket set?

Thanks John.

I believe it's a 6mm Allen key you need, but I stand to be corrected :

Thanks guys  

took the car to the aternator recon place he gave up after 2hrs trying to get it off  

So I'm back home from work so going to try again think it is 6mm now I've got the cam casing off looks like as Johnny says I might be able to get the bracket off the block not sure how the allen bolt would come out tho?

Will also try a blow torch any other advice guys ??

After 3hrs last night & 1hr this morning I've given upthe allen bolt is well rounded,  you can see where prob years ago
attempts have been made to chisel the bolt head to get it started.

So I'm thinking perhaps an angle grinder to cut the alternator off then cut through the bolt and remaining bit of alternator body??

Or could a garage use oxy to cut it leaving a stub of bolt to get some grips on?? Any other options  you can think of ?

take the bracket off the engine, then put it in a vice or something. hammer a suitable socket over the allen bolt and it'll come off pretty easy! worst case just get another alternator and bracket from mk1/2 1.6-2.0 8v.

no need to mess about with grinders and such if the alternator is stuffed anyway!

an alternative is go mk3 alternator setup

Thanks John.

Going to have another go in 5 mins the bracket 13mm bolt won't budge either but thats more trying to get some leverage on it thats the probem.

How many bolts hold the bracket on (2 maybe) or do I have to remove the cam belt & pulleys etc to reveal a few more bolts??

Checked the alternator its had it so if I can get the bracket off then I'm sorted I can either get this one refurbed a new one or 2nd hand one will any alternator fit the bracket I have or is each type a different size etc.

Thanks John.

Update….

Got the alternator off with bracket attached the hardest bit was finding where all the bolts are and gaining access so all being well i hope to have it refurbed at the garage in the morning.

Lets hope I can get a new allen bolt without too much trouble. Thanks for the advice guys

good stuff!

Dropped my Alternator off at the reconditioners at 8.30 this morning picked it up early afternoon all sorted with a 12 month warranty.www.mcalternators.co.uk

Hiya, just read this and I was wondering if you could give me some advice on how to take the alternator out?
I've even watched that video in German… But mines not budging :/ 
Thanks 

if you have undone and removed all the bolts its a case of wiggle and tug till it comes out,. they can be proper tight in the brackets

Hi guys, I am having a similar problem at the moment with my mk1. The alternator was over charging so I got hold of a regulator and changed that now the alternator is not charging at all and I have no battery light on the dash. I had the alternator tested and w as told that it was ok and charging on the test rig, I have cleaned up all the earthing point where it fits to the block. if I take the small wire off the alternator, earth it and turn the ignition on the light still doesn't come on. Does this suggest a break in the wire between the alternator and wherever it goes too (fusebox)?? I'm ready to smash the bloody thing lol.