I have a strange issue with my glow plugs on my 85 300 SD 617. It seems that when my light is out in my dash that tells me a glow plug is burned out. Well it seems when I change 1 at a time because I only believe in fixing whats broke the light on dash works for about 2 weeks and then another g.p. goes it seems it never ends. I would like to go to a manual set up with switch. I have read some posts on this but I am not clear on it. If I go manual will my current still be going thru my relay box? I do like when my light in dash tells me when a plug is blown. Will I still have this if I go manual? I think someone said you need a special solinoid that can take constant 12 volts all the time . Can someone tell me exactly what parts I would need and how to do this? I think if I go to manual set up my glow plugs will last longer as I will only use them when I need to. Tired of changing g.p.'s every 2 weeks. Even though I even ream out the holes before install.