Burnt some wires on a bad jump start battery charge replaced alternator still nothing rpm and speedometer gauges work either Could it be an fusible link?

Yes, it could be a fusible link. Fusible links are designed to protect electrical circuits from damage in the event of a short circuit or overload. If a fusible link is blown, it will need to be replaced before the circuit can function properly again.

To check if a fusible link is blown, you can use a multimeter to measure continuity. If there is no continuity, then the fusible link is blown. You can also visually inspect the fusible link for signs of damage, such as melting or burning.

If you find that a fusible link is blown, you will need to replace it with a new one of the same amperage. You can find replacement fusible links at most auto parts stores.

Here are the steps on how to replace a fusible link:

1. Disconnect the battery.

2. Locate the blown fusible link.

3. Remove the nuts or bolts that hold the fusible link in place.

4. Disconnect the wires from the fusible link.

5. Install the new fusible link.

6. Reconnect the wires to the fusible link.

7. Tighten the nuts or bolts that hold the fusible link in place.

8. Reconnect the battery.

Once you have replaced the fusible link, the circuit should be able to function properly again. If you are still not getting any power to the affected gauges, then there may be another issue that needs to be addressed.