Auto Air Conditioning & Heater Repair: Blower will not blow while accelerating, ford f 150, blower works

Question
I have a 1994 Ford F-150 V-8.  The heater / A/C blower works while idling or when coasting, but while accelerating or cruising (15 mph or more) the blower cuts off.  Changing fan speeds, cycling the system on/off, or change between vent/heater/AC does not help. This problem was intermittent last summer (South Texas Heat), but is now a continuous problem.

Thanks,

Adam  

Answer
Aloha Adam,Yeah I live in Hawaii. Sounds like you have a very common Ford problem with vaccum line that feeds vaccum to the vents and a/c selector. First you need to locate the main vaccum line from the engine intake that should go thru the right side of the firewall into the truck.Sometimes Ford uses plastic vaccum lines that crack and fall apart from the engine heat,not a good design. When you accelerate, vaccum from the engine drops and that`s why the air flow changes from idle. Its takes alittle while to hunt them down, but if you want to save money its takes patience.

Good luck, Davidt