This is a new one. I am trying to replace a back up alarm on this toyotaSo I hook it up 48vdc Put it in reverse works great (beep beep beep) then I use the hydraulics( SCR-Transistor I'm not sure) and it cuts out so I check for voltage drop and it drops a volt or 2. No big deal. I put it in rev and drive a bit and it cuts out.It cut out when the SCR is working. OK So I hook it up directly to the battery(beep, beep, beep) Touch the accel pedal or the hyd and it stops. I check voltage at alarm and there is 48 volts there but is dosn't work while in SCR range WTF And yes I removed the battery from the truck to remove stray battery volts from frame, Which there was alot. Isolated it with rubber and installed.