When the power module receives a signal from the control module, it turns on a relay that supplies +12v to the solenoid and vacuum pump. Then the ground current to the solenoid is modulated thru 2 power MOSFETs (transistors) according to the signal level from the control module. There is a large diode across the MOSFETs to protect them from the reverse EMF that kicks back from the large solenoid.
The problem is that during longer periods of braking, this diode over-heats to the extent that it begins to melt the solder of it's leads at the p.c.b. Then the reverse EMF blows at lest one of the MOSFETs.
I am working on a solution, a relay is not the answer.
Yes, I also have had the Un-Safe Gear power module fail too many times. I am lucky to still be alive after using this unsafe braking system.
I am planning to take the time to repair it myself this time, plus modify it so that it would be much less likely to fail again. I'll try to keep you posted on what I find.
I also have the Fan-Tastic Fan with the rain sensor on my RV and found it frustrating that it would continually open & close while raining due to the sensor being inside under the lid. So I simply relocated the sensor outside of the lid onto the edge of the vent.
Now when it rains, it closes and remains closed until it stops raining (long enough for the sensor to dry off). I love the Fan-Tastic Vents and believe that every RV should have at least one, but I don't know why they don't put the rain sensor outside of the lid where it belongs.
The engine battery is connected to the left side of solenoid "B" and the house batteries are connected to the right side of this solenoid as well as the "coach battery disconnect relay" "A".
So solenoid "B" is used for connecting the two battery banks together for a built-in jump-start.
The cable heading down from the left side of relay "A" may be going to the generator, while the other lead goes up to the self resetting breaker "C".
The lead coming out of the top of breaker "C" should be going to a fuse block inside the coach.
I hope you find this insight helpful.
While the refer is out, you may want to take the opportunity to improve the insulation around it.
What I had found in the hardware stores, was that the water-heater insulation blankets happen to measure 48" wide by 76" tall and consists of 2 inches of fiber glass with plastic on one side. I got one and cut it right down the middle and stapled each half onto the sides of the cabinet walls. Plus, being that each piece was 76 inches tall, the extra was able to be utilized above the refer.
The insulation naturally fluffed out from the walls, but having the plastic protecting it, it pushed right into place when we pushed the refer back into the opening.
It is actually the damper motor that fails.
If you would like to save some money, you may try your hand at repairing that little motor.
Their is a plastic gear bonded to the center magnet of the motor, when this bond breaks, the magnet just spins without turning the gear.
So, you can open the motor by bending back the metal tabs and removing the cover. Then remove the gears to get down to the one that came lose from the magnet. Clean both the magnet and gear with rubbing alcohol, then glue them back together with JB Weld. Reassemble the motor, the oven, and test it out.
The worst that can happen is that you fail to fix the motor, but you were going to replace the motor anyway. On the other hand you may succeed and end up with a motor that would outlast a new one, being that it is put together with JB Weld. Good luck, and now at least you know exactly what failed.