Radiator Fan Not Working 1200 (1986)


Information and questions on GL1200 Goldwings (1984-1987)
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lukeinmexico
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Radiator Fan Not Working 1200 (1986)

Postby lukeinmexico » Sun Apr 05, 2015 9:55 pm



Hello!
I took a ride the other day and noticed my engine getting hot when the bike was running 35 miles/hr and under.
When I got home I realized the radiator fan wasn't kicking on.
I ran wires straight from the battery and the fan seems to work fine.
I tried unsuccessfully to run wires from battery through a toggle switch and fuse to the fan motor to turn on the fan when needed. Long story short, it didn't work. When the fuse was between the battery and the switch, the fuse would blow when I turned the switch off. When I put the fuse between the switch and the fan motor, I fried the wiring (not the bike wiring, just the wires I ran).
From what I've read online, I think I have a bad Thermo switch.
My questions are:
Is there a thread discussing how to check (and replace) the thermo switch?
Is there a thread discussing how to put in a bypass switch to the fan motor?
I know others have experienced similar problems, does any one have any suggestions on how to proceed?
Thanks in advance!



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dingdong
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Re: Radiator Fan Not Working 1200 (1986)

Postby dingdong » Mon Apr 06, 2015 8:57 am

You more than likely have a defective thermo-switch. You're trying to feed a new power circuit to a circuit that is already powered. Thus blown fuse. There is a plug at the thermo-switch with 2 wires. Jumpering those two wires will tell you if the fan is working and you can install your over ride toggle-switch between those two wires. No power just the wiring to the switch.
Sometimes just pulling and cleaning the crud off of the end of the switch will make it work again.

Tom
Tom

A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.

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alwims
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Re: Radiator Fan Not Working 1200 (1986)

Postby alwims » Mon Apr 06, 2015 10:30 am

Here is a pic of my switch. I replaced 2 of those fan switches and wasn't going to replace a 3rd so I took an on/off switch, used trim tape to attach the switch. Ran the wires down and spliced each wire into the wires attached to the thermo switch. Works like a charm. I just watch my temp gauge and turn on the switch when the temp reaches a certain point, 4 bars on my gauge.


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lukeinmexico
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Re: Radiator Fan Not Working 1200 (1986)

Postby lukeinmexico » Mon Apr 06, 2015 2:05 pm

Thank you for the replies.
I appreciate your help!
Does anyone have a picture or diagram showing the wires attached to the Thermo switch that are used for the manual switch? I’m a little confused on which wires to use.
Someone else told me the fan normally has 12v to it already wired, and the thermo switch grounds the fan so that it works. He said normal practice is to wire in a switch on the ground side ahead of the thermo switch so the fan can be activated.
Is this just another way of saying what you’re already trying to tell me?
Thanks!
-Bobby

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tom84std
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Re: Radiator Fan Not Working 1200 (1986)

Postby tom84std » Mon Apr 06, 2015 9:20 pm

Don't know if you know or not. My brother's fan quit working. 84 1200. He wired a toggle switch in. I got the bike and checked. The AGC fuse located under the seat was blown. I replaced the fuse and removed the toggle switch. It's working perfectly.

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lukeinmexico
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Re: Radiator Fan Not Working 1200 (1986)

Postby lukeinmexico » Tue Apr 07, 2015 4:02 pm

Thanks Tom,
Do you know if the 86 has the same fuse?
I looked under the seat but didn't see anything.
Thanks for the help!
-Bobby

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tom84std
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Re: Radiator Fan Not Working 1200 (1986)

Postby tom84std » Tue Apr 07, 2015 5:48 pm

Hmm.. That's pretty odd. Honda duplicates and re-uses circuits to avoid re-engineering whenever possible. If I remember correctly, it's located about center of the seat and to the left of the rear fender. Glass AGC fuse in a white nylon holder and I believe it was a 10 Amp. My brother had wired the toggle switch from the fan to a hot acc wire, but he put the switch beside the air filter under the fuel door. Meaning you had to stop and shut down the bike to either switch it on or switch it off. It made me wonder if my parents had lied to me about him being my brother.

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SilverDave
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Re: Radiator Fan Not Working 1200 (1986)

Postby SilverDave » Thu Apr 16, 2015 12:21 pm

Luke :
The fan is always hot and connects to ground when the rad switch turns " on "....
Which might explain your fuses blew .

------------------------------------------------
I had an explosive overheating a few years ago, so first I rebuilt and cleaned the entire cooling system :
new thermostat, fan switch, cleaned and flushed rad , new hoses, etc, etc.

Then I wanted to install a fan switch which would tell me if the fan was actually running ..
I used a largish toggle switch and a green LEd mounted on the left handlebar .

The 12 volt LED is a diode so it must be wired in the correct orientation.
One can use thin wires for the LED part , and regular wiring for the rest .
Its almost impossible to wire this without clearing all the rad stuff away ,
and even then , the wires in there must be short, so they do not fall into the fan .
Since the circuit Blue-fan-black is always hot, I double shrink wrapped each soldered connection in there ( NOT electrical tape !! )
Here is a diagram :




After two years , I can ( sadly) report that I have almost never used the toggle switch .
Whenever I see the temp climbing to 6 or 7 bars, and think its a good time to turn the fan on, the green light tells me the thermal switch has beat me to it .... LOL...

In other words, the best part of the modification was NOT the toggle switch, but the green LED ... Not what I expected !!

I think these machines should have left the factory with a fan indicator light installed on the dash .

SilverDave

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alwims
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Re: Radiator Fan Not Working 1200 (1986)

Postby alwims » Thu Apr 16, 2015 12:54 pm

Honestly it seems to me you all are making too much of this. Maybe it's different on my 87, but according to the schematics in my Clymer book the only difference is Honda stopped using the 10 amp fuse before the fan on the85, 86 & 87 model and ran it from the fuse block, that tom84std is talking about. The thermal switch on mine acts as a simple connector switch. When the switch gets to the correct temperature the switch closes and completes the circuit. I took a simple manual on/off switch, left the plug still plugged onto the thermal switch, spliced one wire to one side of the wire coming off the thermal switch and spliced the other wire to the other wire coming off the thermal switch. Didn't cut any wires or replace any wires. Now when I flip the switch on my handle bar it completes the circuit that the thermal switch was supposed to do, fan comes on, engine happy.
87 1200

84 1200

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SilverDave
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Re: Radiator Fan Not Working 1200 (1986)

Postby SilverDave » Thu Apr 16, 2015 2:36 pm

And assuming the two grounds are "the same" then my wiring is doing exactly that , vis-a-vis the switch part .
The rest of the wiring was to wire up an indicator LED that worked whenever the fan came on.

SilverDave

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alwims
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Re: Radiator Fan Not Working 1200 (1986)

Postby alwims » Thu Apr 16, 2015 4:05 pm

SilverDave wrote:And assuming the two grounds are "the same" then my wiring is doing exactly that , vis-a-vis the switch part .
The rest of the wiring was to wire up an indicator LED that worked whenever the fan came on.

SilverDave


Dave, I wasn't cutting down anything you said/did. As a mater of fact, I admire what you did and may copy it as I like the idea of a light letting me know the fan is still on. I was just trying to point out to the OP how simplistic the fix is and get him back on the road.

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alwims
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2008 GL1800

Re: Radiator Fan Not Working 1200 (1986)

Postby alwims » Thu Apr 16, 2015 4:15 pm

lukeinmexico wrote:Thank you for the replies.
I appreciate your help!
Does anyone have a picture or diagram showing the wires attached to the Thermo switch that are used for the manual switch? I’m a little confused on which wires to use.
Someone else told me the fan normally has 12v to it already wired, and the thermo switch grounds the fan so that it works. He said normal practice is to wire in a switch on the ground side ahead of the thermo switch so the fan can be activated.
Is this just another way of saying what you’re already trying to tell me?
Thanks!
-Bobby


Bobby I just reread this and no, that is not the way to do it. The thermal Switch is just that, a Switch. The ground it coming into the thermal switch and out of the thermal switch. All the thermal switch does it connect the two grounds at the correct temperature. Nothing more than that. What I did was just add a manual Switch to connect the circuit because the thermal switch had quit doing it's job.


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lukeinmexico
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Re: Radiator Fan Not Working 1200 (1986)

Postby lukeinmexico » Sat Apr 18, 2015 9:21 pm

Thank you everyone!
I installed a working manual switch last week, and went ahead and ordered a new thermo switch from Honda.
I put in the new thermo switch today and took out my manual switch and the fan seems to work fine now. I don't think I would have figured out how to run the manual switch without your help, I really appreciate it. I put in the new Honda thermo switch because I didn't like the idea of forgetting to turn the manual switch on.
Some basic info for someone trying to change out the thermo switch:
1.) The radiator has to come out to get the thermo switch out
2.) I didn't want to take off the cover to the water pump or thermostat, but that would have made the job easier
3.) To get the old thermo switch out I had to use a 27mm combo wrench because I couldn't get a socket to work (the deep well was to big, and the short socket just slipped off)
4.) The job overall was a little time consuming, but not very hard, I think anyone can do it (especially with the awesome people on this forum)

Thanks again for all the advice!
I really appreciate the help!




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