Help! 86 GL1200I Fan not coming on -- sensor switch replaced


Information and questions on GL1200 Goldwings (1984-1987)
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sgtrock1956
Posts: 11
Joined: Fri Jun 21, 2019 8:39 pm
Location: Chicago IL
Motorcycle: 1986 Honda GL1200 Interstate

Help! 86 GL1200I Fan not coming on -- sensor switch replaced

Post by sgtrock1956 »



Good afternooon, and thanks for all the support and information on this site and on YouTube.

The 10A fan fuse is good.

I Followed the YouTube video for removing the and replacing the radiator. I removed the Thermal Sensing Switch from the block and replaced it, and the wiring looked brittle, so I remove and replaced a bit of it and used bullet connectors removed from their insulators and re used the boot.

I took it for a test ride, 20 minutes out and visited a friend. All was good, but fan did not come on. Did not stay long and rode home. Temp Guage moved a hair over the half way mark and the fan is still not coming on.

I pulled the coupler from the physical fan to the wiring harness and tested each lead to the battery using a 12V tester. Neither lead will light the bulb in the tester regardless of whether I connect the other end to Ground or Positive. Is this normal? Or do I have a bad wire going to the Fan?

Can I physically wire the Fan and a switch to 12V? Which wire should go to ground through the switch, and which to 12V?

Thanks in advance.



sgtrock1956
Posts: 11
Joined: Fri Jun 21, 2019 8:39 pm
Location: Chicago IL
Motorcycle: 1986 Honda GL1200 Interstate

Re: Help! 86 GL1200I Fan not coming on -- sensor switch replaced

Post by sgtrock1956 »

I know, I know, I should have read the articles here first. I did. They didn't make any sense to me until I got in and worked on this.

It looks like the best solution is to take off the plug to the thermal switch and put a switch in series with the green wire and ground.. Then when I need the fan, turn the switch on, which completes the path to ground for the green wire and powers up the fan which is already connected somewhere to 12V somehow. Although I could not find a 12V path from ground to either one of the leads on the fan harness.

sgtrock1956
Posts: 11
Joined: Fri Jun 21, 2019 8:39 pm
Location: Chicago IL
Motorcycle: 1986 Honda GL1200 Interstate

Re: Help! 86 GL1200I Fan not coming on -- sensor switch replaced

Post by sgtrock1956 »

I believe it has to be the fan itself. I have a switch on to ground and the green wire and can measure 12V from it to both wires on the connector for the fan. The fan still refuses to come on. Had I done this much trouble shooting before I took out and drained the radiator, I believe I could have saved a lot of time!

froche
Posts: 275
Joined: Wed Mar 12, 2014 1:56 pm
Location: Vista, ca
Motorcycle: 1985 Goldwing Aspencade (GL1200A)
2002 GL1800

Former bikes;
2000 R1100RT
2005 Suzuki Bandit
1979 Yamaha XS1100
1978 Yamaha XS1100 Special
1990 Yamaha XV250
1980 Yamaha XV750
1979 Honda CB750
1968 Triumph Bonneville T120
1973 Honda CB450
1968 Harley Davidson Sportster
1974 Honda CB750
1968 Honda CL72

Re: Help! 86 GL1200I Fan not coming on -- sensor switch replaced

Post by froche »

I just connected a simple on -off switch in parallel with the wires attached to the fan switch. Simply completing the switch regardless of what the fan switch is doing turns the fan on.



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