Jake,
If you sell all the IMSG's you can make with the limited number of seat heater switches you can get your hands on...I have question;
What if I have a seat heater switch, I send it to you, you make the IMSG with my parts, will you then sell it back to me minus the cost of the switch? With that, I think you'll sell more by having your customers supplying you the parts you're short, thus relieving you of your DMS issue.