Testing Glow Plugs

Remove the bar that connects the glow plugs, so they have nothing connected to them. Switch your multimeter to the 200 ohm scale. With the black lead earthed to the cylinder head, touch the red lead on the tip of each glow plug - it should read close to zero (indicates continuity). If it doesn't then that glow plug is dead.

the only awy to test them is out of the motor, you will only be able to test that you have voltage to the glowplug with a multi meter.

gotta say i agree with Phil, been using the continuity test as he describes for years and it nails the weak glow plugs every time. Never pulled one out to test it yet. You should get a reading on the 200ohm scale of 0.005 to 0.009 if they are decent. Much above 0.010 and I like to replace it anyway.

with stuart p, the other auto sparky

you can test it like the others said but it wont tell you JS,

if you wish to test them in the vehicle you will need to test for power at the rail you can do this with your meter and test for voltage, if that is ok you can remove the buzz bar, and test for resistance like the others said, this is about as much as you can do with a std mullimeter, to test further in vehicle you will need a ampmeter capable of at least 20amps and connect this form batt pos to the terminal on top observing how many amps are being drawn and how fast they drop away they should be similar but dont power up for longer than 10 sec as you cant see how hot they are getting.

to test them properly you need to remove them from the vehicle
a ampmeter capable of at least 20amps and connect this form batt pos to the terminal on top while holding the hex of the nut on negative observing how many amps are being drawn and how fast they drop away and the time they take to glow cherry red at the tip NOT HALFWAY DOWN they should all be similar, this will give you an indication as to how long the timer should be glowing them for.

if any need replacing do the whole lot its alot easier than doing the same job again next winter

Stu

Thanks everyone that replied!
Tested the glow plugs the way Phil described and discovered 2 of the plugs were stuffed, Once we had pulled the vehicle apart to change the glow plugs we checked them using a 12 Volt battery...All done now and the mate is happy again!!

Thanks again......Dave