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| | | | Joined: Jul 2013 Posts: 45 Wrench Fetcher | | Wrench Fetcher Joined: Jul 2013 Posts: 45 | Ok, 12 month ago I converted by 54 3100 to 12V having my gen. rewired and changing the reg. to a 12V reg.
This passed weekend decide to convert to an alternator. Bought the alternator harness and wired it up. Seems pretty easy. Start the truck, checked the voltage at the battery while run, 14.25V, seems ok. Turned off the ign. key, but engine stays running. What did I do wrong?
awk | | | | | Joined: Nov 2005 Posts: 6,100 'Bolter | | 'Bolter Joined: Nov 2005 Posts: 6,100 | Hy awk, you are probably using the ignition terminal on the ignition switch as your alternator excitation wire, when you turn the ignition switch to the off position the alternator back feeds the ignition circuit. Depending on which alternator you have, you could install a diode in the alternator excitation wire to prevent backfeeding the ignition circuit, or you could purchase something called DA plug which plugs into the alternators two terminal connection and has the diode incorporated into it, hope that helps. | | | | | Joined: Jul 2013 Posts: 45 Wrench Fetcher | | Wrench Fetcher Joined: Jul 2013 Posts: 45 | 3B,
Thanks, but I believe I'm using the DA plug. I ordered an alternator conversion harness from American Autowire P/N 30370 that has the 2 wire plug and the alternator BAT terminal all wired. I have the brown wire going to the ign "ON" terninal of the ign. switch. Still using the original ign. switch which is only "on or off".
I have a GM 3 wire alternator, with internal reg.
awk
Last edited by awk; 12/08/2014 8:06 PM.
| | | | | Joined: Nov 2005 Posts: 6,100 'Bolter | | 'Bolter Joined: Nov 2005 Posts: 6,100 | Hy awk, I sent American Autowire an "E" mail, they got back to me and said that their p/n 30370 does not contain a diode, their suggestion was to disconnect the two wire plug, start the truck and then try to shut the engine off, if it shuts off with the plug disconnected then it needs a diode in the exciter wire to stop the backfeeding, as I suggested in my first post, hope that helps. | | | | | Joined: Jul 2013 Posts: 45 Wrench Fetcher | | Wrench Fetcher Joined: Jul 2013 Posts: 45 | 3B,
I called them too. They told me that 30370 harness did not have the diode and gave me the spec's on the diode. Picked up the diode last night installed it and all is fine now.
Thanks for the help, another problem solved by the great people on this site.
The diode that Autowire uses is 6amp, 400v, NTE5814. I installed a 6amp, 600v, NTE5815. Could not find the 6amp 400v, NTE5814, but the NTE5815 should still work fine. These are actually silicon rectifiers
awk | | | | | Joined: Mar 2005 Posts: 1,636 'Bolter | | 'Bolter Joined: Mar 2005 Posts: 1,636 | I install a warning light so I know if there is a problem. At least if you lose a fan belt you know when it happens.
But nothing wrong with using the diode either. Glad you got it figured out. | | | | | Joined: Nov 2010 Posts: 1,159 Shop Shark | | Shop Shark Joined: Nov 2010 Posts: 1,159 | | | |
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