The heater blower on my 05 when on high slows down and then speeds back up to speed sometimes. Has anyone else had this happen or have any explaination?

 

Is it when you're idling? Maybe it's your intake heater grid is cycling on and off. It takes a hell of a draw and will dim your lights and slow down your fan.

 

Could be I don't have a clue on this one. It does happen at low rpm's , but not just at idle. Just wondering if this was common or if I've got an electrical problem.

 

If it only happens when you first start the truck and before you have driven very far then it is probably the grid heater. Next time you drive it try to see if it still does it after you have driven a few miles. Good Luck.

 

Watch your voltmeter when it does it. When the grid kicks on it will come on for a few seconds and draw the volts down to about 10 or so then it will kick off and shoot right back up. They cycle on and off when it's below 50 degrees and you're going less than 18 mph I believe. Its normal. See this other thread.

https://dodgeforum.com/m_1049805/tm.htm