If you have an HEI distributor with a Tach Output you can use the Tach Output from the distributor. Due to the high voltage of the signal from the HEI you should use a tachometer filter to prevent damage to the tachometer. Coil Pack or Individual Coils (Distributorless Ignitions).
Yes, thyroid disease can affect your mood â primarily causing either anxiety or depression. Generally, the more severe the thyroid disease, the more severe the mood changes. If you have an overactive thyroid (hyperthyroidism), you may experience: 1  Unusual nervousness. 2  Restlessness. 3  Anxiety. 4  Irritability.
Hypothyroidism in general can cause mood swings, so it is possible this is the cause. In any case, something bad is bound to happen to her if she is not taking her meds. You may want to look at the post 7 above yours, from Summerwind63. She experienced a myxedema coma after stopping her thyroid medicine. Without a thyroid and any supplemental hormone replacement (Synthroid, for example), one can die.