Old style glow plug relay
I was using a test light on my GP relay today to figure out why my 6.9 isn't starting. Of the four terminals on the relay 3 made the test light shine. The terminal that is connected to the positive battery post would not. Is this supposed to happen? Is this an indicator that the relay should be replaced and upgraded to the newer style?
I used the test light on the glow plugs earlier in the day and they all worked. Later, 4 of them no longer worked(thus the new 8 motorcraft gp's).
Oh, the fuel pump, injection pump, one fuel line, all 8 eight injectors, all the return lines have been recently replaced. Any thoughts would be appreciated.
http://www.members.shaw.ca/k2pilot/
If it was attached to a ground, the battery terminal should always show hot.
The small black wire is a ground, so it would not.
The large terminal across from the battery terminal should show hot while the glow plugs are heating only.
The purple wire should show hot while the glow plugs are heating.
If you had it attached to the battery positive terminal,
The battery terminal on the relay would not light the test light.
The small black ground wire would light the light.
The purple wire would light the light, backfeeding the controller.
The large orange and white wire terminal would light the light unless all the glow plugs were burnt out as well as the indicator light in the dash.

Not the best picture, but it is the only one I have that is almost stock.
I do have a manual push button unit from the previous owner of this truck, which I tried yesterday. I'll post when I see the results from the new gp's, thanks.




