I'm having a pre-glow problem with my car, the logical problems are either the glow plug relay or the glow plugs.

Someone on the forum previously told me to check the continuity of the pins on the relay, that they should be between .3 and .7, I believe. I tested those and got some really weird numbers. My tester zeroes out if I touch the ends, and from memory, I got a reading of 1.3 to 1.7 on most, with the #5 glow plug giving some way weird number like 27.4 so I figure that means glow plug #5 is the trouble maker.

I tested each step along the way, the battery puts out 12 volts, the relay at the strip measures 0 volts when off, 12v with the key on, and 12v at the other end of the strip when on. So if I'm seeing this correctly, the relay is fine.

I put a 6/12 v circuit tester (the thing that lights up if it gets 6 or 12v). The tester works. If I touch the end of a glow plug (I could only get to 2 of them) with the key on, it doesn't light up. With the key on, the tester should light up, correct? Could that mean that some of these wires to the glow plugs are messed up or something else?

1991 300d 195k