Original Fantastic fan 1250 no longer spinning.

Lawyerboy

Evening—Latest issue is that the fan, which was working fine for years, even with that mod that uses the knob to slow it like a rheostat. That covid era mod worked fine but now, no longer will the fan spin, and no longer can I change the speed. So, if I want or need to replace the fan, can I do it without removing the frame on the roof, meaning replace guts into the existing frame? I believe I read that I still need access from the top, to screw the blade and motor assembly from the top, but is everything else able to be simply plug and play from inside? TY all

MuttonChops

Short answer: Yes, it is simple to just replace the motor assembly

A bit More:

• Yes, you will need to access from the top.
• Many folks report replacing the motor only to find the failure point was not the motor. So confirm the motor is your issue. Consider trying to run the motor directly from a 12VDC power source. 'Bench Test'
• The Dometic K8017-00 motor assembly is compatible with the 1250 / 4000R fans.

Several sources for purchasing the K8017, like Amazon Item

qhumberd

Before you give up on an old friend, I would check the power circuit as there is a fuse in the fan, and also the switch on the cover. Those are easy fixes. Fans are pretty simple creatures after all.

Lawyerboy

thank you both. I know of the pull out fuse but is there another inside?

qhumberd

I know of the pull out fuse but is there another inside?

There is a fuse at the fan as you mentioned and of course a fuse on the fan circuit. I would check the switch on the dome as that got sticky on mine. Yours might be fine but worth it to check

Here is an AI approach:

The control that stops the airflow if the dome is not raised is called the safety plunger switch (also referred to as the dome safety switch or pin switch). [1, 2]

How It Works

The Mechanism: It is a small, spring-loaded metal pin located on the top exterior frame of the fan housing. [2, 3]

The Function: When you manually crank the lid closed, the plastic dome physically presses down on this plunger. This breaks the electrical circuit and cuts power to the motor so the blades cannot spin against a closed lid. [1, 2, 4]

The Activation: Once you raise the dome by at least 4 inches, the pressure is released, the pin pops back up, and the circuit closes to allow airflow. [2, 4]

Common Issues with the Plunger Switch

Because this switch sits on the roof, it is highly prone to weathering. If your fan will not turn on even when the dome is fully cranked open, this switch is usually the culprit: [5, 6, 7]

Sticky/Stuck Pin: Road grime, sap, and corrosion can cause the spring-loaded pin to get stuck in the "down" (compressed) position.

Loose Mounting Nut: The hex nut holding the switch to the frame can vibrate loose, causing the switch to drop too low to complete the circuit. [6, 8]

How to Fix It

Clean It: Pop off the interior screen or head up to the roof with the lid open. Spray the pin with a tiny bit of electronic cleaner or WD-40. [2, 6]

Exercise the Spring: Press the pin down repeatedly with your finger and let it snap back up quickly to knock away corrosion and loosen the internal contacts. [2]

Replace It: If it fails entirely, the official part is the Dometic K1122-05 Dome Switch, which is inexpensive and straightforward to swap out. [1, 5]