Gird Heater Cycle Problem on '89

[Wiredawg]

A friend of mine has an 89 that the grid heaters only stay on for 4 seconds when he turns the key on before starting at 20 degress and colder. The grid heaters don't cycle, they just come on and turn off after 4 seconds. He has to cycle the key manually. Once the truck is started, they cycle the way they are supposed to.



Appreaciate any help with this one.



Wiredawg