Dalwyn, if you bring the monitor to the sensor, does it work? I took all of my sensors and established a range for each. The monitor will work without being plugged in. So, I set the monitor and sensors on a table, then I walked each sensor away. When the monitor stops reading, you move back slowly until it registers again. That is max "line of sight" signal for that sensor. Each sensor should read at least 40' or further with no obstruction. And you need to know the range of each to inform Mike of your results.
On our 34' there was intermittent signal loss, especially on interstate or major highways with big rigs or crowded with cages. When I added the repeater, I placed it under the left bumper of the truck and tied it to the "running lights" on the driver side. That gave better reception. I added a second repeater in the rear truck window.. that fixed the dropouts for a couple years.
I now plan on repositioning the bumper repeater inside the AS, on a switched power source... hope that keeps things working.
Our AS really are hard to transmit around and the sensors do not have high power to conserve the tiny battery...
Peace and Blessings..