Electrical Problem?

[GBBiker]

Black probe on the main earth point on the engine (alternator mount) and red probe on one of the cables coming out of the black box on the top of the alternator. Can't remember which one it is but try them all for a reading, won't do any harm.

[andrew walker]

many thanks will try that tomorrow, if not 14v then should I assume that i need a new alternator, if 14v then the fault may lie in the wiring?

[Nadjenka]

I might be out of line - but if you have no "warning" lights on the dash (engine and oil), then the alternator is probably not charging. This could be caused by little thing as the bulb in the dash You say all lights went at the same time... again - did you try the simple checks like blown fuse or burned bulb Worth checking before you buy new alternator... Someone will correct me if I missed something...

[andrew walker]

Warning light are working now, the battery was drained, so no need to check the bulbs, it would have been nice if it was something that easy. many thanks

[andrew walker]

checked alternator only pushing out 13.5 v and voltage seem to be fluctuating, do i need a new alternator or will changing the bushes help?

[mat campbell]

I read the manual last night. It says to test between the alternator and earth.
Do this by increasing the revs and keeping it steady but at the same time check the voltage whilst turning all power intensive items on in the vehicle. eg heater fan all lights (horn if you wish ) and see if the voltage drops below 12v. if it does then it says the bushes are likely to be worn.

It also says when idle it should read anywhere between 12-14v but no more than 14v.

[andrew walker]

problem sorted it think, old battery would not start her yesterday, charged the new one overnight put that on would not even turn over again both read 12v, our of sheer frustration put the old battery straight back on started first time, new battery is not charging so going to take it back, anyway did all the checks on the alternator and battery and as previously said the power was fluctuation and going down on my digital meter, went to garage for some tools and found my trusty old multimeter and thought i would try that, it a not digital one, seemed to be reading a good 14v. borrowed my mates digital multimeter and hey presto a good 14.4 v, even with all the bit like light and heater on. all of this because of a fault brand new battery and a faulty multimeter. will get another new battery which i think will sort out the problem once and for all

Thanks for all your help

[andrew walker]

well I opened my mouth too soon, problem not sorted. checked the new battery and was reading 12.98v, thought i would put it back on to see if it was realy knackered and bang started like a dream. yet in the morning it would only barley turn the engine. Whats more when I put the old battery on this morning the indicaters did not flash when you operated the central locking, now its working again. It all seems to be linked with the battery leads, do you think that one of them may be dodgy, had a look and they seem to be ok. Help

[Gaz 270]

a fully charged battery when surface charged removed with the vehicle not running or battery on a bench should read 12.6-13.2 v this however is not the only indication, there are a host of tests that need to be carried out to diagnose this fault but unfortunatly it is too long winded for me to type out the correct diagnostic procedure on here , I would advise booking it into a reputable auto electrician who will pin point the fault in less than 15 minutes(im sure) on some thing as simple as a tranny.