thermostatic switch problem

[Paddy Galore!]

hi gents, need expert opinions please. I've just got the bike back on the road, gave it a service and new battery a couple of weeks back and it all seemed fine. only thing now is I had it standing and idling last week and now the fans won't come on, the temp gauge needle moves slightly when I turn the ignition on but doesn't move as the bike warms up, radiator warms up nicely but no fan, checked fuses and all are ok. this brings me to the thermo switch in the rad, only a single wire to it so how do I test it to see if it works? I had a similar thing on my vf1000 but that had 2 wires so just put the multi meter across those terminals. I don't want to buy one just to try because Honda want 60 bills for it so i'd rather test first to make sure if possible. I doubt it matters but the bike is a 1995 vfr750.

cheers for any help,

gram

[Snoozer]

Touch that single wire to any ground on the frame with Ignition on and the Fan should cycle If it does the switch is most likely at fault.

If it doesn't cycle the fan has an additional earth wire (Diag shows bolt 35 going through ground connection) and sometimes that can break so although the switch is working when the Bikes up to temp it isn't getting a ground so won't complete the curcuit to cycle the fan.

I have had it where the coolant is that low the switch never gets up to operating temp to switch the fan on.

 

Edited March 20, 2019 by Snoozer

[Paddy Galore!]

thanks dude, I checked the coolant when I gave it a service so the levels should be ok, i'll double check that first though, then start stripping back the plastic.

much appreciated,

gram