Automotive application as the title suggests.
The equipment is to be powered by a DC - DC converter.
Absolute max input voltage is 32V; any more and the manufacturer states warranty void.
The equipment is to be used in both 12 and 24V systems.
Unfortunately under certain conditions input can exceed the 32V limit.
A combination of MOV /Fuse has been suggested. Sadly a MOV which might be OK at 1 mA leakage current may be unsuitable at higher currents in that the terminal voltage may be way over the 32 V limit.
A lower voltage MOV on the other hand may start conducting rather heavily at the acceptable voltage .
Recommendations are sought to the possible over voltage solution on the economic side.
Transient suppression diodes , zener diodes etc to be considered.