What did I do wrong
 

I have a 95 f250 with a 7.3 l powerstroke. I bought the truck in august and no problems. It got colder and I started having trouble with cold starts. I tested my glow plug relay and found that it was not working. I decided then to make a push button activation for the glow plugs. I cut an extension cord and placed wire connectors on the ends. I placed the wire connectors on the two small posts on the relay. My thinking was that if that was an open circuit I could use the button inside the truck to close the circuit and activate the glow plugs. The first time I used it worked perfectly. I saw the amps draw down and the truck fired right up. The next time I tried the amps didn’t draw down as much. Then the third time it didn’t work at all. I then removed the glow plugs and found that all 8 were not burned up. They were autolite plugs,and from what I hear I am lucky they didn’t swell and break off. I assume that I did something wrong in this process causing the plugs to fail. Any ideas on what I did.

I would be looking at the switch, or the wiring... Or even the relay... Glow plugs should be fine, although I would ditch the Autolites and put some Motorcraft plugs in there...

:c:

put a new relay in it and be done with it. your trying to outsmart the ford engineers for why??? i don't see any benefit of what you are trying to do. the relay only cost 52 dollars.