ing trigger wire Yel/bk stripe to batt iso no power

[bobwhite]

its a 2014 coachman freelander on a CHEVY 4500 chassis and the yellow wire w/bk stripe from the ignition circuit of the chevy cab to the batt idolator sends the key on / eng on signal to the idolator to switch the cab alternator on to charge the house battery's. i tapped into that wire to run a small 12v 10 amp air pump and it popped the ? fuse...in 10 seconds...too much amps. my question is does anyone know where the fuse is for that circuit. it has to be an independent fuse as nothing else has failed. cab starts... all lights powered... no codes etc. starts and runs and charges the cab battery. if i jump 12v to the feed on the isolator it works fine as long as i keep it with a voltage source. i checked the wire as far up the coach as i can and nothing . i key on checked all power at the fuses at the cab and no blown fuses in the fuse boxes as well as all relays are functioning. where is the fuse? my electrical guy says there is an independent fuse to that wire somewhere ?// help/

[bobwhite]

just a quick note. its where coachman hooks up the wire from the cab ing circuit to the coach idolator. can't find any wire diagram of either i can see the Chevy wiring diagram from Mitchell and the house set up from coachmen but not any info on how coachman runs that circuit.