zardos Posted August 29, 2009 Share Posted August 29, 2009 After my alternator bearing seized and snapped the drive belt I need to replace my alternator (A 100Amp multi V drive belt type). With the job finished I started the vehicle to find the ignition warning lamp on and battery voltage unchanged. I double checked both connections for cleanness and tightness and all looks good. The old alternator was charging fine up to the point it seized and the belt snapped. I am seeing 14+ volts between the alternator stud and earth on the body when running. The main alternator power cable is showing 13+ volts when disconnected from the alternator and not running ( indicating a good connection to the battery ). Any Ideas Please Quote Link to comment Share on other sites More sharing options...
errol209 Posted August 30, 2009 Share Posted August 30, 2009 After my alternator bearing seized and snapped the drive belt I need to replace my alternator (A 100Amp multi V drive belt type). With the job finished I started the vehicle to find the ignition warning lamp on and battery voltage unchanged. I double checked both connections for cleanness and tightness and all looks good. The old alternator was charging fine up to the point it seized and the belt snapped. I am seeing 14+ volts between the alternator stud and earth on the body when running. The main alternator power cable is showing 13+ volts when disconnected from the alternator and not running ( indicating a good connection to the battery ). Any Ideas Please Cor, that's a stumper. Apologies if you've already thought of these (you know your way round a voltmeter, major stride forward ...). With the ignition on, the motor stopped and the alternator harness off, what voltage are you getting on the warning light (brown/black) at the alternator end? should be 12V+, and I think this will be true. Slighty harder, but if you re-connect the harness and start the engine, what is the voltage at teh akt. end brown/black connection now? Logically it ought to be 14V+, but I think you'll get nearly zero. If so, check that the brown/black is connected to the right terminal, as just because the replacement is similar, doesn't mean it's the same. Have you given it some revs too? Meanwhile, I'll wash up and see if I can think of any more. Quote Link to comment Share on other sites More sharing options...
p38rr Posted August 30, 2009 Share Posted August 30, 2009 Sounds to me like the wiring between the altenator and battery is at fault. Try connecting a charge wire from the altenator straight to the battery positive and see if the problem disappears. Could be you have a break in the wiring somehow when you changed the altenator!! Quote Link to comment Share on other sites More sharing options...
SteveRK Posted August 30, 2009 Share Posted August 30, 2009 I'm not sure i understand what the problem is? Are you saying that the alternator is charging but the ignition light is on? this is quite possible if the alternator retains enough residual magnetism to flash up the windings without an external 12 volt supply. If this is what is happening then the 12 volt ignition feed is connecting to ground, or not registering 12-volts from the alternator output. Quote Link to comment Share on other sites More sharing options...
Doctorvaltar Posted September 2, 2009 Share Posted September 2, 2009 Have a look at this link, page 8 mentions the light staying on. http://www.qxcomponents.co.uk/tech.pdf Quote Link to comment Share on other sites More sharing options...
zardos Posted September 6, 2009 Author Share Posted September 6, 2009 All Fixed now. Replaced with a non faulty alternator. Thanks for the suggestions. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.