There is so much crap out there on this subject for something so simple.....Yes if you press the A/C it should trigger both fans??? now that is all well and good "IF" your A/C works??? Or your pride and joy was built with it as most UK spec Mx-5's are not, or it has been removed from your...

Tools needed...
1/4 drive ratchet, 10mm socket and extension bar,
Pointed pliers, pliers, or hose clip pliers,
Utility craft knife,
Silicon spray lube,
New hoses, supplied by Autolinkmx5 for this guide.

Should take a hour ,but there are no medals for rushing any job...

********Health and safety...