Re: Starting issues, 1995 7.3
After thinking about it today, it sounds like a couple of glow plugs may be bad, but not sure. Test them if you are in doubt, as for checking the relay, the way I check mine is I hook a voltmeter between the two large posts on the relay, key off should read battery voltage, key on/glow plugs on should read .5 volts or less. A reading of more than .5 volts means your relay is working, but the contacts are getting bad, and not supplying good voltage to the glow plugs, and should be replaced soon. If it reads battery voltage constantly, and clicks when the key is turned on, the relay is junk. If it doesn't click, or reads battery voltage at all times, it is time to test the relay controls. But I don't think you will have to go there yet.
Things to consider: on a cold truck, the glow plugs should stay on for almost 2 minutes when you turn the key on, no need to cycle the key, the WTS light is not hooked to the GP's. I turn the key on and count 45-50 seconds then she starts, down to about 8 degrees. ( Bugman learned me that trick, before I joined the forum. Thanks Bugman!)
I have only used this test on relays, which do not have a shunt on the GP relay, if yours has the shunt, I'm not sure this test will work. (The shunt looks like a piece of accordion sheet metal bolted under one large post on the GP relay)
I am just assuming the connections on your relay and batteries are clean and snug. If not, fix that first!
If you replace your relay, HillHavenFarm posted a link to a good source! I still have a stock relay, but will upgrade when it needs replaced.
Hope it helps, just my .02
Sent from my E6810 using Tapatalk