Mark you're not going to hurt anything by driving it the way it is. What will happen is you'll continue to get the short cycling you've been getting, and that means when it's cold you'll get no start. That plug isn't connected at all so the controller reads it as a red hot glow plug and shortens the cycle. The good news is that you do not have to replace the controller or the glow plugs to do this right. The correct harness is $90 or so from International. You can replace the connectors with butt connectors, and some here have had good success with that, I could just never find the type that would stay connected and tight long term, seems to be an odd size. If money is tight and you want to drive the truck, just plug in the block heater. In the updated blocks (roughly 85 and later) this won't hurt anything. Also you'll be able to stat it just fine even without the glow plugs. Just whatever you do, don't get tempted to use ether as a starting aid unless you darned well know what you're doing and have disabled the glow plugs for sure. The only problem with using the block heater is that of course you have to have some place to plug it in and also the cold timing advance won't kick on so it warms up more slowly, 2-3 hours of the block heater will get you 130*F coolant.block temp, it should start anywhere. I bet if you get a butt connector that fits you will have 8 functional glow plugs and an easy starting truck.