Thor Forums

[javelin]

So I am attaching a Intellitec document that describes the operation of latching relays in general and the typical control wiring of both coach and chassis disconnect switches and their related LED lamps located at the steps. This “may not” be your exact wiring though. You need to determine which specific Intellitec BCC you have.
On this example document (under Fuses), it seems that there are two fuses on each latching relay. One fuse provides 12vdc from the respective coach or chassis battery through the fuse to the corresponding switch at the steps. This becomes the control voltage that will then operate or release the corresponding latching relay. So if this fuse is blown on the chassis disconnect latching relay for example, you will not have 12vdc at the chassis battery disconnect switch that will allow you to turn the latching relay on or off. The second fuse on each latching relay apparently powers the associated LED lamp at the stairs for the corresponding disconnect. Since you have the chassis disconnect light always on.....it implies to me that your chassis disconnect is latched in the “on” position so chassis battery 12vdc is passing through the chassis disconnect latching relay and coming back to the steps to turn on the chassis disconnect LED through a current limiting resister in series with that LED. When you turn off the chassis battery disconnect switch I suspect that you do not hear the clunk of that relay releasing (as you should) so it is probably staying latched on; therefore LED stays on. So why is this happening? Maybe one of the fuses is blown on the chassis battery latching relay that sends 12vdc back to the step disconnect switch which is then used to control the operation or release of that latching relay. It could also be that the latching relay has just failed in the on position......or many other things. I don’t know this BCC but “if” the attached pdf matches your wiring, you could check for an open control fuse on the chassis disconnect relay or check for control 12vdc at the chassis disconnect switch itself (don’t confuse LED 12vdc with the control 12vdc). I don’t know how involved it is to access latching relays for your BCC, so if it is buried behind a circuit board.......then remove shore; turn off gen/engine; disconnect both battery string grounds (coach and chassis) and ensure those grounds do not accidentally touch chassis. Carefully obtain access to the latching relay and see if it has the fuses described in the pdf. If it does, test the fuses with a multimeter set to continuity (or ohms). The fuses should show short (tone on) if they are good. All of this may not even apply if your BCC is not per attached basic document of course. You may need to obtain the assistance of a mobile tech or take it in for repair to your Dealer to be absolutely safe; or if you do not have a meter or basic electrical test knowledge.