If you drive a vehicle that carries a CA number, this applies to you!
A Driver for one of our rental company customers was complaining of a broken A/C and no defroster. When the driver would try to turn on the defrosters it made a clicking noise.
13 CCR 1232 Motor Carriers shall ensure all
The defroster is an essential part of a vehicles accessories, and therefore must be operational to pass a CHP inspection.
The above link will take you to a .pdf from the California Highway Patrol titled "Understanding A Terminal Inspection." where the code excerpt was taken from.
Our mechanic started the job by removing the seats in the truck cab to allow better access to the dashboard. He then pulled the dash apart to gain access to the heater control box. This allowed him access to the blend door flap. That is where the issue was.
Have you seen the handy little dash tray that some trucks come with?
It sits right in center on the top of the dash board. It's so convenient for pens, change and other miscellaneous little items. Little items that can fall right through the defroster vents and cost the owner of the vehicle quite a bit of money in repairs.
This is where those "little items" end up. In the heater control box blend door area. The "little items" jammed the blend door and prevented it from opening up the defrosters. Eventually the gear drive broke from multiple attempts to open. The clicking noise the driver heard was the broken gear trying to catch.
In order to replace the broken gear, the entire heater box had to be purchased. There is a lot of labor involved in removing and replacing the entire heater box. The AC evaporator is inside the HVAC box and requires evacuation, removal and recharge of fluids upon re-installation. The temperature sensor, blower motor, actuators and resistor also need to be removed and reinstalled on the new HVAC box. In order to save our customers some money in labor, we removed the blend door and gear (interior parts to the left of the line below), and installed only those parts into the old HVAC unit. Now the customer has a spare HVAC box for the future!
Moral of the story:
Don't leave items on your dashboard! Even if there is a special tray just for it!
The Shop Blog
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