97 7.3 diesel starts hard

[wewille]

Agree, an amp clamp is the fastest, most accurate way to test the overall health of the glow plug system. You can save a lot of time measuring overall current draw before messing around checking individual glow plug resistance. That is like wacking it with a hand full of crushed glass. Where are you measuring the 6v at? The output terminal of the relay or the b+ terminal?

[Ziob34]

all his glow plugs tested fine resistance wise (around 1.5 ohms).....he's getting only a 6 volt output on the relay which i'm told should typically be close to or around the input (12 volts) if the relay is working properly. maybe i'm wrong i suspect he's just got a bad relay thats just worn out and has a bad connection?