I've got a 2008 F-350 with the Diesel motor. It has had a tapping noise for the last few months that seems like it is coming from the heater coil under the dash on the passangers side. Is this typical as it ages or is it something I should look into. It is a steady tap with the engine running and does not seem to speed up or slow down with engine speed.

Thanks

 

Could be one of the HVAC blend door motors. I have an 08 F250 and there is a blend door making noise under the center dash area. If I have the HVAC control in floor/vent mode, it isn't as noticeable but if I put the system in floor mode only, it's all you can hear. Tick,tick,tick,tick,tick and an occasional whir sound like an electric gear motor is working much too hard.

I'll be bringing it to Ford to get it fixed. From my research here and around the net, this is a typical problem with these trucks.

If that's what your issue is...

 

Thanks for the reply. Sounds like the same problem.