truck acted like alternator cut out .voltage w/ engine running 11.8.overnight batterys dead and grid heater boot melted housing discolored.manual says both replaced as a unit.wonder if heater damged etc.anyone have a similar experience,and advice?

 

Sounds like the relay got stuck closed. the contacts might have gotten a little carbon on them and they eventually weld shut when all of the current has to go thru a reduced surface area. The grids pull a total current of 180 amps. That's a heckof a lot of current, so it doesn't take long before your batteries are fully discharged. So the relay is probably toast. I'm not sure what you mean by "grid heater boot". Do you mean the grid heater housing located under the intake horn? If so, I think mine is aluminum. Can you elaborate? In the meantime, if you pull the relay, you can continue to drive her until you get things fixed.

 

the boot over the electrical stud on the heater

 

OK. Then I think I'd just replace the relay. I was looking at the boot on the wire today, and unless there's bare wire showing, I'd just leave it undisturbed.

 

replaced relay today, $70.00 at dealer.also bought gaskets for heater assembly thinking maybe I should take a look at it.wondering how durable these elements are and if they could come apart and scatter through the engine.After knowing what I know now I probaly could have got out and smacked relay when volt meter woudn't come up.I put a test light in truck , probably wll never happen to me again but maybe will help someone else.Thanks for the reply.

 

My understanding is that you could put a ford starter solenoid on for less money and they are built a little heavier.
Tom

 

Putting a ford part on a CUMMINS, how disgraceful.