[Brandon Willoughby]

So I have a very odd problem. I've asked a few people about it and they said they'd never heard of this. I have a 2005 Titan LE 4x4 off-road. When I turn my heat on all I get is cold air. Overtime of me running down the road with my foot on the pedal I get heat. As Soon as I let off the pedal it goes back to cold air. Also when I turn the fan on I hear a popping noise over and over and over. It also does it when I turn the vehicle off. The popping sound is definitely coming from under the dash. Any ideas will be greatly appreciated. Thanks in advance.

 

[dubyam]

If you get heat with higher RPM, I'm going to bet your coolant is low.

 

[AZPRO4X]

It's Vacuum related...

 

[dubyam]

I'm not following you on the vacuum issue. That's not to say it's not that, but I was unaware there was a vacuum switch source or anything like that in our system - but I'm also no expert on our heater systems. Teach me and I can learn, though.

 

[Mach1tosh]

Low coolant and air in the plumbing.
Burp your cooling system.