IAC Survival Kit Harnesses Only 

Replacement pair of harnesses to use with 221-1090.

The advantage of the harness is to prevent a failed IAC from damaging the PCM, which is $2,000+ to replace. The harness contains a replaceable fuse that will blow and prevent the shorted IAC from damaging the PCM (ECU-Computer). This is a common failure point blamed on the IAC but the root problem isn't the IACs, it's the fact that Mercury is exceeding the duty cycle on many of the engines that causes them to overheat and short out. Used on 496MAG, 496MAG HO, 525EFI, 600SCi, 662SCi, 700SCi, 850SCi, and 1075/1200SCi applications.