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View Full Version : 1985 dodge ramcharger fusible link


sailor don
Dec 4, 2009, 10:35 AM
1985 dodge ramcharger alt blows and won't charge tried 2 alts 1 volt reg and nothing works car runs on battery what next?

TxGreaseMonkey
Dec 4, 2009, 11:19 AM
Thoughts:

. Remove and fully charge the battery, making sure there's nothing funky going on with it.

. Check for codes. The ECM plays an important role with many alternators. The FR signal communicates to the ECM how "hard" the alternator is working to meet the electrical demands of the truck, including the battery and any loads which aren't monitored by the ELD. This square-wave signal varies in pulse width, according to the load on the alternator. The ECM places, approximately, 5 reference volts on the wire. The voltage regulator will drop this signal to approximately 1.2 volts, in proportion to alternator load. The ECM compares the electrical load (ELD) signal with the FR (Charging Rate) signal from the alternator and uses that information to set the idle speed and turn the alternator on and off. This helps fuel economy. Therefore, make sure the ECM is okay.

. Check all under dash and under hood fuses with a test light or multimeter.

. Check the wiring harness and under hood and under dash fuse boxes. Ensure all wiring is hooked up properly. Clean all connections, particularly where the mega alternator wire attaches to the under hood fuse box. Remove and clean fuses in under hood fuse box. Examine and clean battery cables.

. Examine ignition switch for wear, pitting, or melting.