glow plug ?

can anybody tell me how much amp draw all 8 glow plugs working correctly have? and where the best place to check the draw is. ?

They draw a lot. It is like plugging in eight cigarette lighters all at the same time.

so set your multi-meter to "ALOT" ! :morons:


Actually, I was wondering the same thing. Since you have to stick your meter in the circuit, I was thinking the best place is right at the connectors, but you'd wan't to make sure your connections were good just so enough current could flow.

Is there an easier place to insert a meter in-line?

I'm guessing as far as draw goes, they are either going to pull a lof of amps, and all 8 should be close to the same. Any plug that doesn't perform the same as the majority has the issue.

For testing purposes, testing ohms is just as reliable. Test ohms. Test voltage. V/R=A

Ohms law rocks. http://en.wikipedia.org/wiki/Ohm's_law

So, where do you measure resistance through? Through the plug?

I've never tried to actually measure glow plugs like this... can you walk through the basic set up to get the resistance measurement?

well i figured since i am having some issues that could be glow plugs instead of something else. i though if each plug draws 2 amps.. i would need 16 amps worth of drop no? and if i had 12 amps i would know 2 are not working well or the whole set is weak kinda thing, and go from there.

The amount of current they draw depends on how long they have been on. I do not remember the exact amount but it is a lot more then two amps. You can play with one out of the truck to experiment but it takes some juice to heat up that whole tip red hot.

For resistance, place one lead on the end of the glow plug (with it unplugged) and put the other lead to ground. For voltage, with the glow plug plugged in, and the glow plug relay energized, measure from the end of the glow plug to ground.

Check amp draw when the engine is cold, using an inductive ammeter. Each bank should pull over 80 amps initially, then slowly taper down as they heat up.

If it is lower than this, you need to check each plug individually. Each glow plug should have an initial current draw of at least 20 amps. Any initial reading lower than 20 amps indicates a problem with the glow plug.

907DAVE said:

Check amp draw when the engine is cold, using an inductive ammeter. Each bank should pull over 80 amps initially, then slowly taper down as they heat up.

If it is lower than this, you need to check each plug individually. Each glow plug should have an initial current draw of at least 20 amps. Any initial reading lower than 20 amps indicates a problem with the glow plug.

Click to expand...

Thanks. That's what I was looking for