stee 1FM 0 Posted December 1, 2008 Hi Guys Ive got a bit of a problem with my 1fm, and i think it may be the alternator but i would like a bit of advice before splashing out on a new one. Right to start with: When the car is offmy battery is reading 12.53v with my multi metre When i turn the car on it is reading 13.56v When the engine is running and all the electrics are on e.g lights, heater, demister ect it goes right down 13.13 and my battery symbol is dimerly lit. When i put the multi metre on the neg on the battery and the positive on the alternator with all the electics running it reads 13.00 Is this normal???? Is my alternator about to give up on me??? Or is it something else??? Also when i turn my lights on dipped beam they dont come straight on, they come on then brightern up could this be due to my suspected to my alternator faults or something else?? Any input will greatfully recieved Stee 1fm Share this post Link to post Share on other sites
jackherer 543 Posted December 2, 2008 When I had the dim battery light issue it was due to the main power wire (battery to starter then alternator) that had corroded, it eventually snapped at the ring connector on the alternator leaving me stranded and nearly starting a fire! As you are seeing reasonably high voltages but lower on the alternator itself it does sound like a bad connection, but as you have the multimeter + on the alternator when you see a lower voltage it sounds like it might be a bad earth, probably the one on the gearbox. Delayed headlights is a new one for me, that could be an alternator fault by the sound of it, but I would definitely check the wiring first as its likely to be in poor condition if its original. Share this post Link to post Share on other sites
welshpug 1,657 Posted December 2, 2008 When i put the multi metre on the neg on the battery and the positive on the alternator with all the electrics running it reads 13.00 what do you get at the battery end of the positive lead? Share this post Link to post Share on other sites
ablister 31 Posted December 2, 2008 as above, check with your leads at earth point on alternator and also at negative terminal post on battery. Same with positive side; check positive post on alternator and on battery. Also need to check amp output but will probably not be able to do that with your multimeter as it'll be too high Share this post Link to post Share on other sites
stee 1FM 0 Posted December 2, 2008 hi guys thanks for the help.i'll check the wiring and get back to you all with what i find. how would i go about checking the alternator AMP output?? stee1fm Share this post Link to post Share on other sites
ablister 31 Posted December 2, 2008 you'll need an amp clamp which is a like a multimeter with a clamp, hence the name, which surrounds the battery positive cable and can measure the current through the wire (or anything else you need to check the current flow on). Most multimters only measure up to 10amps but alternators can give around 100amps (don't quote me on that) so will damage the meter if it isn't fused. But wouldn't worry too much about that, just try and get about 14v. Chech voltage with engine running lots of consumers on; heated rear screen, lights, heater fan etc to check it under load Share this post Link to post Share on other sites
