so i ran a fifty foot x-cord from the garage and pluged in. first night worked great. second night it poped the breaker sometime, cause it was hard starting the next morn. so i went out and bought a timer and a light up x-cord. pluged in and looked out my window hours later, and the cord was still lit up, so i just chalked it up to voltage. next day i go plug the truck in, and it poped the breaker. So after playin with it for awhile, i figured it might be a short under the hood? I can plug the x-cord in to anything and it works fine, includeing the roomies toyota block heater. but it pops the breaker as soon as i plug it into my truck. Did i miss something? happen to anyone else?

You didn't mention what size breaker. If it's a 15 amp, you could be maxing it out - especially if there is anything else on the line. Also, breakers do get weak with age - especially if they are tripped periodically, so you may try swaping it out with another breaker, or plugging into another circuit. If it's a 20 amp breaker, and you don't have anything else on that line, then I would suspect the heater - either the cord or the heater itself.

You didn't say what guage of extension cord that you bought. If it is a 16awg and you combine that with the current draw of the block heater, a possible weak breaker and the voltage drop/loss on 50ft of 16awg, Yes the breaker will probably trip. Try plugging your truck in somewhere that you don't need a 50ft cord. Put a amp meter on the breaker in question to see what it is tripping at. My guess is that the breaker is weak and combining that with the long extension cord and high current draw of the block heater, you have problems. Change the breaker.
One more thing, check the male cord end on your truck. Could be that the wires are shorting there. Better yet, just put a new end on and be sure.

thanks i'll check the breaker, just thought it was odd that it work fine for the roomies toyota block heater, it's probley just less voltage.

I was going to mention the length of the cord is going to equate into this as a possible problem..

I have a 100 foot plus a 50 foot 12 gauge cord on a 20 amp breaker and i dont trip mine.

Your 12awg cord is good to handle 20amps. The voltage drop on 150ft isn't enuf to cause problems. Your block heater is only drawing +- 6-7amps. You've got plenty of headroom.

Hey I had same problem . I found that the fridge that I put out in the garage during the summer{Cold Beer:D } was on same circuit and would trip every now and then making for hard starts in cold weather. The block heater pulls a steady 1500 watts. And the fridge pulls that just for a few seconds on start up and would over load the breaker. So either go bigger ext cord to keep amps or find what else is on that breaker. O and keep ends clear of water .Ive pluged in truck first then plug in to outlet .Ive been hit with the current trying to plug in when water is melting off hood and wet hands:eek: :eek:

My guess is you bought a cheap extension cord right? A guy really shouldn't use anything BUT 12ga. with block heaters in a Diesel engine. Also, you'll need to make sure you bought a 15 amp timer and not one of those little wimpy ones.

Its not a voltage drop that is the problem its the current draw. The more ext cord you add increases resistance in the circuit which draws more current. On initial plug in it could very well spike to almost 20 amps plus, especially if your using ext cords. I highly recommed using a 30 amp timer with GFCI protection, use a 20 amp circuit (30 if possible), and avoid ext cords is possible. If you have to use cords then check that they have the least amount of resistance as possible while still able to carry the current load.

ok i'll try it out, 65' of x-cord is a bit much. i just wanted a light up cord so i could look out the window and see it but i'll work on it today.

Go to your hardware store and you can buy lightup plugs. They look like the plugs you'd use to plug a 3 prong cord into a 2 prong outlet.

Our d-max's have 1000watt heaters 8.333 amps. watts divided by volts (120) = amps

thanks for the help, the root of my prob was the light up x-cord, turned out to be 16 guage. i think i got it fixed now.