We have a Trimble/CIH AFS 132 lightbar unit that the display screen has quit working on. It works on the lightbar itself but not on the receiver or whatever it's called. Can't adjust the swath width now or adjust the brightness of the lights when it gets dark.

When I first plug it in you can see some bars come across the screen but then it goes blank. The backlighting does come on.

This unit was left plugged in for 3 weeks or better, draining the batteries on the tractor completly dead. Could that have something to do with it?  

 Could this be something simple or do I need to contact Trimble? 

Thanks for any and all advice.