Ammeter Bypass/Bulkhead Connection Fix Weak Link:
Poor wiring design at bulkhead connector and ammeter. Models Affected:
Dodge full size trucks/Ramchargers up to 1980 What Happens:
Full alternator current goes through a poorly-designed bulkhead connector, to the dash wiring, then to the ammeter, back through bulkhead connector, to the starter relay and finally, the battery. Over time, the heat caused by the full alternator output going through the resistance of these connectors, can cause the bulkhead connectors and the gauge to melt, and possibly cause a fire. Cheap Fix:
To fix both issues, first cut alternator output wire leaving it long enough to reach the Starter Relay, lengthen wire if needed. Connect a new fusible link that is four gauges smaller than output wire (example: 10 gauge wire, use 14 gauge f-link). Connect this to the Battery Positive Stud of the starter relay.
Next, eliminate the connections at the bulkhead and replace them with wires that will go through the bulkhead connector. To do this, disconnect the bulkhead connector and remove the two charging wires from both the bulkhead (at the firewall, from inside vehicle) and the harness connector (engine compartment).
Now drill out both sides of the bulkhead connector where the charge wires originally were. Make the holes slightly larger in diameter than a 10 gauge wire. Feed two lengths of new 10 gauge wire through the holes in both the harness connector and the bulkhead, now reconnect harness to bulkhead. Connect the engine compartment side of both of the new wires to a single 16 gauge fusible link and connect this to the Positive stud on the Starter Relay.
Remove Gauge Cluster to access Ammeter and remove both wires from back of the meter. Connect these two wires together. Connect the new wires coming through firewall to the original ones that were removed from the firewall connector, it doesn’t matter which wires go to which.
Now install the much more useful Voltmeter to monitor the charging system.
Note: It is extremely important to use the crimp, solder and insulate technique with ALL connections made here.Contact:
Credit for this procedure goes to Mark Hamilton from Mad Electrical.http://www.madelectrical.com/electricaltech/amp-gauges.shtml