Help needed, electrickery problem

[Russ]

Ok, new Granetelli exhaust cutouts fitted, for anyone not familiar with these they have a little box with chip and micro relays in it, connected inline which enables one touch operation so just tap momentary switch up or down to open or close instead of holding switch down. Problem is the cutouts keep blowing inline fuse.
After several days testing for plate dragging/dodgy cables/ etc I have puuled all wiring back out from fuse box etc and found that when directly connected by crocodile clips to a separate or disconnected battery the cutouts will work fine all day long untill they flatten the battery. great.
When I reconnect the vehicle negative terminal back to the battery, (with ignition still off) the next time I use the cutout switch the inline fuse blows again
Never had any problems with other stuff, modern radio etc. Mini fuse rated @7.5 amp but have also blown a few 10's and 15's as well just for good measure. Dont know where else to go with this really apart from dustbin and buying some qtp's so any help gladly received. Could there be a live to earth or something that this box would be extra sensitive too?

[ScottyDave]

Wired back to front maybe? Check connectivity between the wires and the body of the cut out.

[Dave999]

or the cut out is in back to front

does it have a flap and does the flap have to overcome exhaust pressure to open
if there is a way to fit them that:

1) allows them to stay sealed at high revs
2) allows minimal or less pressure against them when they try to open

you will use less current when opening them

it will be a solenoid based linear actuator or some such they draw massive current when not moving and that reduces something like 50% once there is movement and gets smaller the faster the movement is.

much like an electric motor...

turn them round so the main exhaust pipe flange side faces the outside and see

and the same for scottydaves comment wired so that open is closed and closed is open can mean opening is against an unrealistic level of pressure


Dave

[Russ]

Thanks for replys guys, finally got back out now rain gone away for a bit, problem sorted, and as always something simple, tested individually and found right hand cutout culprit, took it back off and took rubber shroud off and saw prob immediately. neg was earthed to body by shoddy factory quality control on soldering so as soon as switch changed polarity there was a conflict of interest you might say . Obviously worked fine when tested untill it was earthed by fitting the thing

cutout fubar.jpg (42.86 KiB) Viewed 945 times

Thanks Scottydave for pointing me in right direction

[ScottyDave]

Result nice when its simple fix.

[Russ]

Hehe kicked myself for not finding it sooner, never mind all refitted and back in asbo mode now when required

[Dave999]

ah yes....bloody hell shoddy workmanship or somebody kicked it off the truck during shipping