I bought this wonderful 1995 Ford F350 Crew Cab 7.3 PS Diesel truck this summer and as of lately (now that the temps are dropping below 45) I am having one heck of a time starting it. In fact, temps were 26 degrees a couple of mornings ago and it took no-kidding nearly 20 minutes of fooling around with the starting process to get it started. I keep reading that it could be glow plugs, glow plug relay switch or even the possibility of needing a block heater. If I do have to replace the glow plugs and ideas where exactly they may be located? Any other suggestions? Thanks!