truck wont start when cold out unless plugged in. last week block heater started to trip gfi plug in. is there any way to test block heater to make sure its ok. checked cord for visiable shorts looked good. thanks for any help provided.

 

Do you have a Ohm meter?

Your checks should be between power lead and neutral, then Power lead to ground, and ground to neutral.

Get those real quick, I will see what mine are and at least we can get a comparison for you.

Now, in my experience, I hate GFI's, and have chased more then my fair share of problems just to find out the GFI was at fault.

Sorry, Welcome to FTE!!!!

 

15 ohms from hot to neutral
.9 megg from neutral to ground lead
1.5 megg from hot lead to ground

 

i got 141.3 when i first touch hot and neutral then nothing and nothing between hot and ground nothing between ground and neutral. thinking heater is shot

 

Between hot and neutral is what you should be most concerned with, Neutral and ground/ground and hot, you want nothing.

I would suggest inspection of your cable, but yes, sounds like the heater is shot.

 

replaced heater and cord no blown breakers. thank you for all your help

 

No problem!!
Now if you would, go out and do you ohm checks with a new heater, this will give you a reference latter on down the line.. Sort of a Predictive Maintenance thing.

 

Your the man Pat, Nice job helping the OP with his heater problem.

 

14.6 on new heater thanks again

 

What setting on your meter did you use to check your block heater.

Sorry, I'm Electrically challenged.

 

200 ohms is the lowest mine goes