ya i have noticed thow on my 12v weather i plug mine in or not it still cycles for the same amount of time, the only advantage i see with it is it stays close to the house so i dont have to walk as far. i dont even notice a difference in the amount of time for the heater to start blowing hot air

 

I almost wonder if your grid heater is workin. It may just be drawin amperage but not heating up right and that would deffinately explain the rough idle.

 

I'm also thinkin that your idle may need adjusting.But you need to do it when your engine is cold.Because mines doing the same thing right know.As for your lights going dim then bright after you start it,mine does that to. But it's because the grid heaters are cycling.

 

i thought it was because of the cylcle that the lights go dim

 

yea im pretty sure yall are right. it only does it for a few mins.

 

get a new grid heater

 

On the drivers side battery there is two wires going to the grid heater relays on the fender - these wires are fusible links. If you have a multimeter, have a look at them and check for continuity.