Compression Ignition Addict
Join Date: Aug 2008
Location: Madison, WI
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No, the glow plug relay should NOT buzz.
GPR test - check the voltage at each big terminal, key off. One terminal should show battery voltage (12.5-ish), the other should show zero. Turn the key to RUN and check again. The "always hot" terminal will show lower voltage, probably 11.5-ish. The other terminal should now show voltage, a little less than the always-hot terminal. But if the difference between the two, while the key is in RUN, is more than 0.3V, the relay is weak and should be replaced.
Glow plug test - disconnect each UVCH, and measure resistance from each outer pin to ground. Resistance should be just about 1.0 ohms. Much more or less, or "open" (infinite resistance) indicates that glow plug is faulty, or a wiring problem under the valve cover.
Are you sure you got a relay that does _not_ ground through its mounting base?