91 temperature gauge stays on zero

So one of the issues with my new to me ‘91 is the temperature gauge stays at cold. It doesn’t move up at all. The bike warms up, it doesn’t run like its cold. I think the sending unit has scale on it. Is it easy to install a new one or should I plan on a pita?

I'd look at the wiring connections first. Mine was flaky. Sometimes it worked other times it stayed cold. It was a corroded connector at the sending unit.

Check the connection for the temp sending unit to make sure it is connected, clean and tight. It is located on the right side of the engine, up front on the joint that has the two prong fan thermo switch. It is a single prong connection just behind the chrome guard cover.

That is the first place I would be checking.

Rick F.

Thanks guys, I checked the connection and presto! The temp gauge works! Thanks very much

Yup! that's the usual cause, that wire is easy to accidentally knock off...

Just had this last month on my 86. Remove the aluminum colored trim piece trim piece from the right side of the radiator, and it is right there up high. A little contact cleaner and slid it back together and was good to go. About 10 minutes.

Any chance you guys can post a pic of this? I noticed my temp gauge isn’t working either and I don’t know what or where the ‘sending unit’ is.

Thanks in advance,

tim

Any chance you guys can post a pic of this? I noticed my temp gauge isn’t working either and I don’t know what or where the ‘sending unit’ is.

 

Thanks in advance,

tim

Sorry I had to really make this vid a short one Banks but I only had 1 minute of memory left on that confounded SD card. Hope this helps!! If one of the club guru's dont show up with a definite yes,, it is the blue wire to prove me correct here,, I will double check a schematic and verify.. I am 99.99999% sure it is though cause I had to doodle with mine on a couple of my bikes to fix a gauge problem..

The text on the vid at YouTube reads:

One of our friends on VentureRider.org asked if anyone knew the location of this sending unit on his Yamaha Venture touring bike as his temp gauge had stopped working. Failure of the gauge caused by a loose or failed connection on this sending is not uncommon and fairly easy to fix once you remove that little guard attached to the radiator cover with two screws. There are two sending units/connections in this location - one for the gauge and I believe one for the fan. Going from memory here, I believe the blue wire leading to the brass colored sending unit behind that cover and above that black hose is the one for the gauge. Hope this helps you in some small way Banks and maybe even some other 1st Gen rider looking for this info out there in cyber land!! If your reading this, and riding a Yamaha Venture new or old, you should join the party at VentureRider.org,, lots of good folks/fun/stories happening there at our club! Get out and ride,, Puc

This is the coolant joint and it is located under the right side of the bike right behind the radiator side cover trim

If you notice the single round pin on the lower part of the coolant joint, that is where the temp gauge connects. Make sure it is clean and the connector makes a tight connection and see if that fixes your issue.

Rick Fink.

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So is it the wire that is attached to the solid ‘probe’ on the bottom of this part? I know folks said it’s a blue wire, but mine seems to be green. I popped the wire off and shot some cleaner up in there and put it back on. I’ll fire it back up in the morning and see if the gauge reads once warm.

‘Thanks again all’!!

Well thanks to Puc I found the sending unit and the temp probe. My wire is green, but I took it off and shot some cleaner in there and popped it back on. Took her for a ride today and still no luck. Hmmm...

The thermometer wire is green with a red stripe on the 1988 (and others). In addition to cleaning the bullet connector, crimp the female part of the connector slightly to tighten the connection. Clean the male part of the connection as well. Trace the wire to the instrument cluster and insure that the connection at that end is good. Check for continuity from the thermo-unit end of the wire to the instrument cluster end. Check for 12 volts at the thermometer/temperature gauge, the brown wire. Ground the green/red wire with key on. The gauge should go full scale. Check the black ground wire for tightness on the cooling system "joint" where the temperature sending unit is mounted. Clean and tighten the ground lug/screw.