Temp Gauge or Sending Unit?
- Wingnut95
- Posts: 30
- Joined: Wed Jul 08, 2015 4:32 am
- Location: British Columbia, Canada
- Motorcycle: 1995 GL 1500 SE
Temp Gauge or Sending Unit?
Hi Wingers
I have a '95 SE GL1500 and the temp gauge stopped working over the winter (parked). Looking for some direction on how I determine if it's the sending unit or the gauge that's gone before I take it all apart. I've checked and both fans come on when it heats up, but the gauge doesn't budge. Any instructions on how I might test both would greatly help. I'm mechanically inclined, but terrible when it comes to electrical stuff.
I've noticed a bit of antifreeze after riding it, but not sure if that's coming from the overflow or a leak.
I've searched the Forums and haven't seen anything on testing. My apologies if I've overlooked it.
Thanks,
I have a '95 SE GL1500 and the temp gauge stopped working over the winter (parked). Looking for some direction on how I determine if it's the sending unit or the gauge that's gone before I take it all apart. I've checked and both fans come on when it heats up, but the gauge doesn't budge. Any instructions on how I might test both would greatly help. I'm mechanically inclined, but terrible when it comes to electrical stuff.
I've noticed a bit of antifreeze after riding it, but not sure if that's coming from the overflow or a leak.
I've searched the Forums and haven't seen anything on testing. My apologies if I've overlooked it.
Thanks,
Love to ride!
95 SE
95 SE
-
- Posts: 1
- Joined: Mon Mar 08, 2021 2:15 pm
- Location: Parkersburg Wv
- Motorcycle: 1983 gl1100 1995 st1100
Re: Temp Gauge or Sending Unit?
Find the sending unit on engine. There may be a separate one for fan. Usually the gauge one only has one wire. Unhook the wire and( with key on run) ground to engine. The gauge should slowly go to hot. The sender works by varying the resistance to ground as it gets hotter. By just grounding the wire, it just thinks it's real hot!
- bellboy40
- Posts: 988
- Joined: Fri Nov 27, 2009 1:13 pm
- Location: Brewton, AL
- Motorcycle: 2000 GL1500SE Candy Spectra Red
Re: Temp Gauge or Sending Unit?
Does the fuel gauge work? They both get power from the same relay (#3 tail/main relay). If so, then you will need to do some checking on the connectors to the sensor. The easy one to get to is under the right fairing pocket. It is C55, a 13 pin white connector. The green/blue wire is the one going from the sensor to the gauge.
C22 is a 6 pin red connector over the fans. The green/blue wire in it also. You will have to take off some fairing parts to get to it.
The coolant sensor for the gauge is mounted on the thermostat housing and is hard to get to.
Maybe you will get lucky and find the relay bad or one of those connectors has some corrosion.
Good luck.
C22 is a 6 pin red connector over the fans. The green/blue wire in it also. You will have to take off some fairing parts to get to it.
The coolant sensor for the gauge is mounted on the thermostat housing and is hard to get to.
Maybe you will get lucky and find the relay bad or one of those connectors has some corrosion.
Good luck.
- Wingnut95
- Posts: 30
- Joined: Wed Jul 08, 2015 4:32 am
- Location: British Columbia, Canada
- Motorcycle: 1995 GL 1500 SE
Re: Temp Gauge or Sending Unit?
The fuel gauge does work so I’ll check the relay under pocket first. Do I ground it with key on to see if I get a response or use a meter to determine a response on the meter for the relay?
Love to ride!
95 SE
95 SE
- bellboy40
- Posts: 988
- Joined: Fri Nov 27, 2009 1:13 pm
- Location: Brewton, AL
- Motorcycle: 2000 GL1500SE Candy Spectra Red
Re: Temp Gauge or Sending Unit?
On the C55 connector, ground the green/blue wire, and with the switch turned on, see if the gauge goes up toward hot. I'm not sure if the side you want is male or female but whichever one goes toward the gauge is the side you want. It won't hurt if you ground the side toward the sensor.
- Wingnut95
- Posts: 30
- Joined: Wed Jul 08, 2015 4:32 am
- Location: British Columbia, Canada
- Motorcycle: 1995 GL 1500 SE
Re: Temp Gauge or Sending Unit?
No relays under front right pocket, on junction connectors. Did find 2 relays under front lower cover. Are those the ones you are referring to?
Love to ride!
95 SE
95 SE
- bellboy40
- Posts: 988
- Joined: Fri Nov 27, 2009 1:13 pm
- Location: Brewton, AL
- Motorcycle: 2000 GL1500SE Candy Spectra Red
Re: Temp Gauge or Sending Unit?
Not relays. It is connectors I was referring to. That last picture above looks like the right place. Was that taken under the right side pocket? The connector in question there is the white one with 13 pins. Ground the green/blue wire and see if your gauge goes to hot.
- Wingnut95
- Posts: 30
- Joined: Wed Jul 08, 2015 4:32 am
- Location: British Columbia, Canada
- Motorcycle: 1995 GL 1500 SE
Re: Temp Gauge or Sending Unit?
Yes, those are connectors under right pocket. Didn’t see a green blue but I’ll look closer tomorrow and give it a shot. Thanks for your ongoing support. Much appreciated.
Love to ride!
95 SE
95 SE
- bellboy40
- Posts: 988
- Joined: Fri Nov 27, 2009 1:13 pm
- Location: Brewton, AL
- Motorcycle: 2000 GL1500SE Candy Spectra Red
Re: Temp Gauge or Sending Unit?
Here is the wiring diagram for the instrument gauges. I don't know if you have this or not but it will be a big help in trying to find the problem with that temp gauge.
- Wingnut95
- Posts: 30
- Joined: Wed Jul 08, 2015 4:32 am
- Location: British Columbia, Canada
- Motorcycle: 1995 GL 1500 SE
Re: Temp Gauge or Sending Unit?
Awesome! I was searching online last night for one of these diagrams.
Thank you! This is such a great online community.
Thank you! This is such a great online community.
Love to ride!
95 SE
95 SE
- Wingnut95
- Posts: 30
- Joined: Wed Jul 08, 2015 4:32 am
- Location: British Columbia, Canada
- Motorcycle: 1995 GL 1500 SE
Re: Temp Gauge or Sending Unit?
I have been able to confirm that the gauge is working
Can someone confirm if access to the sending unit is behind the fan on the left side?

Can someone confirm if access to the sending unit is behind the fan on the left side?
Love to ride!
95 SE
95 SE
- MikeB
- Posts: 3805
- Joined: Fri Dec 04, 2009 12:54 pm
- Location: Tacoma, WA
- Motorcycle: 1998 - GL1500 Aspencade
191K Miles
2017 - GL1800 Audio Comfort
28K Miles - Contact:
Re: Temp Gauge or Sending Unit?
There is a Coolant Temp Sensor on the right intake manifold. And a Sending Unit on the Thermostat Housing.
This is #23. I'm not sure which one is the correct unit.
Last edited by MikeB on Wed Mar 17, 2021 4:07 pm, edited 1 time in total.
MikeB
1998 - GL1500 w/184,500 miles ~ 2017 - GL1800 w/13000 miles
USAF Avionics Communications Tech - 1968 - 1986 / Flight Engineer C-130E - C-141B - 1986 - 1992. Retired
Industrial Maintenance Tech - 1992 - 2014
Retired in Tacoma, WA
1998 - GL1500 w/184,500 miles ~ 2017 - GL1800 w/13000 miles
USAF Avionics Communications Tech - 1968 - 1986 / Flight Engineer C-130E - C-141B - 1986 - 1992. Retired
Industrial Maintenance Tech - 1992 - 2014
Retired in Tacoma, WA
- bellboy40
- Posts: 988
- Joined: Fri Nov 27, 2009 1:13 pm
- Location: Brewton, AL
- Motorcycle: 2000 GL1500SE Candy Spectra Red
Re: Temp Gauge or Sending Unit?
Here is the relevant page from the Honda service manual on removing that sender unit. Yes, you will need to remove the left side fan to get to it.
- Wingnut95
- Posts: 30
- Joined: Wed Jul 08, 2015 4:32 am
- Location: British Columbia, Canada
- Motorcycle: 1995 GL 1500 SE
Re: Temp Gauge or Sending Unit?
Thanks to your help I’ve identified the sending unit as the problem, and where to locate it. Parts on order and hope that this fixes the issues.
This is a fantastic community of Wingers and I appreciate the assistance. Not easy caring for a 26 year old bike, but together we can.
Thank You!
This is a fantastic community of Wingers and I appreciate the assistance. Not easy caring for a 26 year old bike, but together we can.
Thank You!
Love to ride!
95 SE
95 SE
- MikeB
- Posts: 3805
- Joined: Fri Dec 04, 2009 12:54 pm
- Location: Tacoma, WA
- Motorcycle: 1998 - GL1500 Aspencade
191K Miles
2017 - GL1800 Audio Comfort
28K Miles - Contact:
Re: Temp Gauge or Sending Unit?
Great job Wingnut95.
MikeB
1998 - GL1500 w/184,500 miles ~ 2017 - GL1800 w/13000 miles
USAF Avionics Communications Tech - 1968 - 1986 / Flight Engineer C-130E - C-141B - 1986 - 1992. Retired
Industrial Maintenance Tech - 1992 - 2014
Retired in Tacoma, WA
1998 - GL1500 w/184,500 miles ~ 2017 - GL1800 w/13000 miles
USAF Avionics Communications Tech - 1968 - 1986 / Flight Engineer C-130E - C-141B - 1986 - 1992. Retired
Industrial Maintenance Tech - 1992 - 2014
Retired in Tacoma, WA