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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: 85-K100-Cafe on July 24, 2017, 09:03:02 PM

Title: Fan Not Turning On
Post by: 85-K100-Cafe on July 24, 2017, 09:03:02 PM

Hello,


The fan on my 1985 K100RT isn't coming on. I let the bike idle for 10-15 minutes and it did not turn on. All the fuses on the motorcycle are good. Is there a way to pinpoint the issue between the temp sensor, temp relay or a bad fan? I am trying to figure out how can i test each individual part to nail down the issue.


Thanks

Title: Re: Fan Not Turning On
Post by: Laitch on July 25, 2017, 05:23:20 AM

Quote from: 85-K100-Cafe on July 24, 2017, 09:03:02 PM

The fan on my 1985 K100RT isn't coming on.

Does the overheat indicator bulb light during that interval? Has it ever lit?
http://www.motobrick.com/index.php?topic=5045.0 (http://www.motobrick.com/index.php?topic=5045.0)

Title: Re: Fan Not Turning On
Post by: rbm on July 25, 2017, 05:25:01 AM

Can you easily spin the fan blades by hand?  It's possible that the fan is seized and needs replacing.

Title: Re: Fan Not Turning On
Post by: johnny on July 25, 2017, 09:47:12 AM

greetings...

1st thing i do is jumper 12v to the fans under tank connector to make sure its running and i feel for air flow...

sometimes the motor runs butts blade donts turn...

process of elimination... i go fan 1st and work backwards to relay 2nd and sensor 3rd...

butts im betting it didnt getts hot enough to trigger the fan in that time frame...

j o

Title: Re: Fan Not Turning On
Post by: 85-K100-Cafe on July 25, 2017, 10:53:27 AM

Quote from: Laitch on July 25, 2017, 05:23:20 AM

Does the overheat indicator bulb light during that interval? Has it ever lit?
http://www.motobrick.com/index.php?topic=5045.0 (http://www.motobrick.com/index.php?topic=5045.0)

I bought the K as the previous owner was converting the bike into a "café racer" so it doesn't have the factory gauge cluster.

Title: Re: Fan Not Turning On
Post by: 85-K100-Cafe on July 25, 2017, 10:54:08 AM

Quote from: rbm on July 25, 2017, 05:25:01 AM

Can you easily spin the fan blades by hand?  It's possible that the fan is seized and needs replacing.

I can spin the fan blade freely by hand

Title: Re: Fan Not Turning On
Post by: 85-K100-Cafe on July 25, 2017, 10:55:19 AM

Quote from: johnny on July 25, 2017, 09:47:12 AM

greetings...

1st thing i do is jumper 12v to the fans under tank connector to make sure its running and i feel for air flow...

sometimes the motor runs butts blade donts turn...

process of elimination... i go fan 1st and work backwards to relay 2nd and sensor 3rd...

butts im betting it didnt getts hot enough to trigger the fan in that time frame...

j o

How do I jump the 12v to the fan under the tank connector?

Title: Re: Fan Not Turning On
Post by: johnny on July 25, 2017, 11:37:06 AM

greetings...

disconnect fan side from loom side... jumper wior from + to connector and jumper wior from - to connector...

j o

Title: Re: Fan Not Turning On
Post by: 85-K100-Cafe on July 25, 2017, 12:13:16 PM

Quote from: johnny on July 25, 2017, 11:37:06 AM

greetings...

disconnect fan side from loom side... jumper wior from + to connector and jumper wior from - to connector...

j o

Thanks, will try this tonight

Title: Re: Fan Not Turning On
Post by: jakgieger on July 25, 2017, 05:22:51 PM

This thread  (http://www.motobrick.com/index.php/topic,6702.msg45871.html#msg45871)contains the wiring info that may be useful...scroll up for testing options.