First, let me say my B.I.R.D was bad.
(Battery Isolator Relay Delay). As soon as I turned on the coach batery disconnect, the relay would 'pick', causing the chassis baterry to be connected to the coach batts all the time. Hence, when the coach batteries died, they took the chassis battery with it.
Secondly, the tech support folks at Intellitec, who make the BIRD, are extremely helpful and knowledgeable. (GS could learn alot from them)
According to them, the Diesel BIRD should have been coupled with the appropriate isolator relay. However, it had the gasser relay (different resistance coil as well as lighter duty contacts) with the diesel BIRD.
As close as I can determine, the 'Diesel' BIRD was put in my coach at the factory. I called the dealer from which the motorhome was originally purchased and who did all the service on it, and they have no record of replacing the BIRD in my mh.
I installed the new BIRD for a gasser from RVparts.com and it seems to be working correctly. I also have to replace my coach batteries. They no longer hold a charge very long.
Ron