Troubleshooting Lid Won't Open After New Circuit Board Installation

Updated 06/22/2026 | Published 06/12/2026

Products Featured in This Question

Replacement Printed Circuit Board for MaxxAir Powered Lift RV Roof Vents w/ Exhaust Only Fan

(120)

$112.64

Replacement MaxxFan Plus 4-Speed Roof Vent with White Lid

(101)

$218.74

Question:

I have a Maxxfan 4751KS. Stopped working...totally I purchase and installed a MA00-04751KSX circuit board. Now the fan works, BUT the lid will only raise a fraction of an inch and stop. I can fully open and close the lid manually, so the operatorfoot is functional. The tracks of the lid mechanism are clean and greased. I applied direct voltage to the lift motor and it runs well without hesitating. So, what is going on here? Is the lift motor failing under strain from lifting the lid? I dont want to keep parts-swapping trying to fix this issue. A new lift motor is $54.02. Im already into this for $111.81 paid for the circuit board. A complet new fan assembly is $211.00. Id rather fix the issuebut well under the expense for a new fan, and the work of removing and installation of a new fan.

asked by: Michael R

Expert Reply:

Hi Michael, since the issue started after replacing the circuit board, I'd first verify that the new board is the correct one for your 4751KS and that all connectors were installed in the proper locations. Since the lid moves freely by hand and the lift motor runs when powered directly, I'd be hesitant to replace the lift motor until the board part number and wiring have been confirmed.

expert reply by: Robin H

Michael R.

6/16/2026

I returned that circuit board. The original is a MAXXFAN 4751KS 4751KSU05 PCB(printed on the original circuit board What is the replacement circuit board for this unit that you stock and can guarantee it to be the correct one?

Robin H.

6/16/2026

@MichaelR that would be the # MA39FR.

Michael

6/22/2026

I ordered and received circuit board #MA39FR from etrailer as you suggested. I hooked up the new circuit board to the MAXXFAN and the lid raised and the fan came on. Great!, But, I immediately smelled a hot electrical odor. It was coming from the circuit board! I immediately disconnected it. So, I noticed that the lift motor seemed to me to be running a little slower than expected and a bit louder while it was energized. I compared it to another MAXXFAN in my camper, and sure enough the sound was different between the two. So, I removed the lift motor from the fan I have been working on and put in a vise and connected 12V to it. Motor seems to run fine, one direction and the other. However,if I leave the motor running a couple of minutes while bench testing it, the exterior housing of the motor becomes very hot to the touch. Do you think I need another lift motor? Is there resistance to an extent in the motor that it is overwhelming the circuit board casusing the heated odor from the circuit board? And, yes while I had the lift motor off I was able to easily crank the lid up and down manually. No restrictions there.