1990 GMC 1500 starter module burn out

I have a 1990 1500 truck with starting problems.
I have found a temporary fix for mine. The starter module keeps going bad. Replaced 4 in past 1 1/2 years. Keep burning out. last module had only 75 starts. One minute it starts - hour later doesn't.
May start one day not the next. Use mainly for plowing. However, module goes bad with normal use.
Put new coil in and doesn't help.

Thanks.

Rath: banghead:

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