Detach the cable from the negative terminal of the battery and remove the distributor cap. Using an ohmmeter, check the coil by measuring the resistance between the positive and negative terminals to assess the primary resistance for specific engine models, and compare your reading with the specified coil primary resistance. Next, measure the resistance between the positive terminal and the high tension terminal to check the secondary resistance for different engine models, and compare this reading with the specified coil secondary resistance. If either test yields resistance values outside the specified range, replace the coil. For replacement, detach the cable from the negative terminal of the battery, remove the distributor, and take off the coil dust cover. Label and disconnect the electrical wires from the coil terminals, then remove the four coil mounting bolts to separate it from the distributor assembly. Installation is the reverse of removal.