View Full Version : Thermostat connection to the Fan?

03-19-2016, 12:08 PM
Hi, not got a pic as I didn't have time and can't seem to find one online.

My 91 Shdow vlx, the bottom of the thermostat has a pin connector, pointing downwards, and I was told this connects to the fan, well I can't find any such connection?

Do you know which one I mean?

It's polished silver, looks like it would have a rubber cap over the 2 connections.

Also a part I have identified is the 'sub cord wire' the green wire that comes from the thermo, I am guessing this is an earth? Where on 'earth' does it go?

03-19-2016, 4:25 PM
Are you asking which wire(s) connect the coolant temp sending unit (fan switch) to the fan itself? And where n the harness to find them?
I'd start with the manual or at least download a diagram.
Don't guess at wire colors, at least trace. "Earth" is the same as "ground", get it? And unless it's a Brit bike, 99% of the time the frame and/or case(s) is ground. Watch out for rubber mounted engines...

03-19-2016, 5:31 PM
You don't always need an exact year manual. I suggest getting as close as you can, perhaps comparing later and earlier manual schematics.


Google some Honda Shadow forums. If you are looking for that schematic here, cool, but brand specific forums normally work best for wiring questions. Someone can take a pic of those manual pages for you.

You can also wire fans by verifying hot to fan motor, then physically tracing the ground which is typically switched to operate the fan. You can trace by continuity check with a meter or using a test light. Tracing wires means you KNOW which is which, handy since many old bikes have been modified and sometimes there are wiring changes affecting only specific batches.

03-19-2016, 5:55 PM
If memory serves on the one I dealt with there was a switched hot wire to the fan then a wire from the fan to the sensor and then a wire from the sensor to ground. which pin you use on the sensor doesn't matter and if the fan runs backwards swap the wires. If you use a constant hot the fan can turn on with the key off possiably causing blood loss.

03-21-2016, 9:18 AM
Hi, I can't locate this wire even on the diagrams? I don't even know what it looks like, also can't see where ot connects to the fan?

03-21-2016, 4:21 PM
Hi it is this one. (the point to the left) That point we belive to be the 'temp send' which sends signal to an 'idiot light' on the dash, though I have now changed my rev counter so don't have this light.

http://s23.postimg.org/gf4stbbon/Screen_Shot_2016_03_21_at_22_13_39.jpg (http://postimg.org/image/gf4stbbon/)

Is this really important this piece? I read elswhere it's not too important and other people run without it.

Love to hear some feedback.

03-25-2016, 10:24 PM
I think it's just the sending unit for the dash coolant light. I'm pretty sure the fans temp control sensor is built into the fan wiring. Put power on the fan and the temp control switch works. Without the thermostat.