I was just cruising through the FAQ thread an came across a bit about the fuel heater. What are the symptoms, if any, of one not working.

Thanks

 

there are no symptoms of one not working if your fuel isn't gelling and plugging up the filter,as this is the devices sole purpose.
a bad dose of fuel with water in it in the winter can plug up the filter too.
when your fuel filter begins to plug up (due to contamination or gelling) then the "fuel filter" light will come on.shortly after,the engine will begin to run rough and then stall.it will not restart again until the filter is clear.

if your truck sits a lot,and you finally head out in very cold weather (down around 0 F) with a tank full of summer blend.you could be sorry and wish you had a fuel filter heater.in this scenario,the small filter heater simply wouldn't be able to keep the cloudy fuel from gelling up and plugging the filter after replacement/cleaning though.you would need to add some diesel 911 and put as much winter blend (or better yet straight k1) in the tank as you could fit.
or lets say,you run across many states where the blends at the local stations may not be blended high enough for the climate your headed too.you could find yourself wishing you had a filter heater.
if you fuel up when you know your local stations have switched over,and you drive locally,the odds are pretty low you'd need a fuel filter heater.

Diesel Winterization
10/30/2013, Craig McCue

 

Thanks, that's good to know.