Is there a way to test your glow plugs to see if they are still good or not? For some reason I think that you have to test how many ohms/resistance or something like that? Could you guys fill me in on how to do it exactly, and also what good readings are and bad readings. Thanks!!!

If you disconnect the lead connector on a glowplug and Put a multi-meter between the wireconnector and glowconnector you can read volts and ohms(with power off).


I use a simple 12v test light and touch each glow connector while someone turns the key to "on" to power them. The turbo side is harder but not impossible.


glow plugs are good if the test light "lights".


Ohms should be 1.2 with power off.


Volts should be in the 11.0-12+ range.


amps 11+Edited by: quantum mechanic

Can you check them out of the vehicle?

You can visually inspect the tips for damage. If they're all mushroomed or otherwise damaged you'll know it.

no way of checking with a multimeter out of the vechile though?

You can test Ohms resistance out of the vehicle. and with a 12v source you could check the plug out of the vehicle. I think it's easier to use the wiring harness and block as 12v source and ground and check them in place.

Remove the connector to each plug when testing it -


Glow plugs should read about 1.2 ohms, whether in or out of the engine.


Infinite ohms indicates an open plug.


Just remove the connector when testing each plug.


A test light to +12v will be bright if plug is good, will not light if plug has burned open.


Remove the connector when testing the plug.

You can also use an amp meter.


I think they are supposed to start out at about 16 amps then drop to about 11 and stay there.

Infinite ohms would be a bit cold huh?


Thanks gmctd!

a battery or battery booster can check them out of the vehicle, hold the body of the glowplug against one terminal, and a hot wire from the other terminal to the connector, if it lights up, its a good one.

a battery or battery booster can check them out of the vehicle, hold the body of the glowplug against one terminal, and a hot wire from the other terminal to the connector, if it lights up, its a good one.





that might get too hot to hold too


LOL