Why Wouldn't MaxxAir 4900 Motor Run

Updated 05/20/2026 | Published 05/18/2026

Question:

I have 2 MaxxAir 4900N fans that have lids work, but motor turns off when started. Checked input voltages, running at 13.9 vDC, Have 2022 Renegade 40ERB so looks like boards are old type sensitive to higher DC voltage. No you folks have a newer replacement board for the 4900N Mine is 10B21276NZ P2v4.1 Pl

asked by: Gerald B

Expert Reply:

The MaxxAir 4900K is going to use the Replacement Printed Circuit Board # MA10A21275K. Do you have lithium batteries? This issue is really common when using lithium batteries as they run at a higher voltage typically especially when charging.

expert reply by: Jameson C

Rick

5/20/2026

About a year ago I replaced my board for the Maxxfan due to strange behavior (beeping and closing randomly). This behavior seemed to start after switching to lithium. Since replacement, all seems back to normal.

Jameson C.

5/20/2026

@Rick glad it fixed the issue!

Matt

5/20/2026

I bought the replacement board and it did not solve my problem. The fans are extremely sensitive to voltage. If it’s over just a little bit it will fry your board again. Best bet is to just rip out all the electronics in it and add on a controller from amazon for 20$. That prob going to be the only way to fix it. I’ve seen very very few vent fans get fixed by replacing the board. It’s kind of a waste that they make these fans so junky and archaic. I’d go with a nomadic if my poops the bed again.

Eric A.

5/20/2026

We used the replacement boards on our unit and have had no issues. They function as they did with the original.

Mikeb

5/20/2026

The replacement board worked fine for me. I also replaced the manual keypad as condensation had caused some corrosion. The keypad wasn'wasn't the issue with the original board, which was a thermally related intermittent operation issue. Everything is good now. Mike