I'm trying to wire up the sti auto spray switch to my headlight washer pump which is powering my IC spray jets. I have the illumination part of the switch working fine.

I have connected a live feed (AC spliced from the radio) to pin 3 of the switch. Pin 5 of the switch is then connected to the coil live of a normal four pin relay. i have an earth for the coil as well. I then have another live feed in (again splied from AC of the radio) and earth for the last two pins of the relay for the n/o terminal arm thingy.

Idea being when the switch is pressed the coil is energised and the arm on the relay powers the pump. But it keeps blowing the radio fuse. Obviously i understand its the radio fuse because i've taken an AC feed from the radio, but I can't work out why the fuse keeps blowing as I'm pretty sure its wired correctly.

someone please help?

 

either the relay is pulling too many amps for the radio fuse rating or its not wired correctly. i would put a direct fused feed from the battery or main live feed

 

What's the size of fuse? The pump will have an initial current kick when it is started up and then stetle down to several amps- the ERL water injection pump sees 15 Amps when initialised.
Try some higher rated fuses but if 10 Amps is still blowing then there is something else wrong. Is the headlight spray pump still wired into the normal wiring or has it got its own layout for the IC spray?

Nick