Author Topic: Re: Cooling Fan Activation Time Interval (Read 14991 times)

rbm · « **on:** March 31, 2015, 10:42:59 PM »

Cooling circuit:

Ground pin E will simulate overheating to the temp relay. The fan should start and the overtemp light illuminate. Proves the temperature relay is functional.

Jumper A2 to 45 will bypass the temp relay and the fan should start. Proves the fan works.

Jumper A3 to ground and the overtemp light should illuminate. Proves the warning light functions.

If you want an override switch to turn on the fan when you desire, wire up a SPST switch to Pin E and ground the other side of the switch. When riding, flip the switch and the fan will start. Overtemp light on the dash indicates the override is in use.

johnny · « **Reply #1 on:** May 12, 2016, 08:48:00 PM »

Filmcamera · « **Reply #2 on:** February 02, 2017, 05:43:29 PM »

I did this today and it works great. My only issue wa that the numbering on my relay etc was different. For others who may have the same issue the wore you need to splice the switch into is blue/yellow. Also my temp warning light does not come on when I turn the fan on so I suspect that is the reason the fan operation was bad, looks like I have a faulty temp sensor - though the temp gauge works so I am not sure exactly what is busted.

Either way I now have a working manual fan override switch!

Laitch · « **Reply #3 on:** February 02, 2017, 05:49:04 PM »

Quote from: Filmcamera on February 02, 2017, 05:43:29 PM

. . . looks like I have a faulty temp sensor - though the temp gauge works so I am not sure exactly what is busted.

The temp gauge is usually connected to a fitting on the water pump. It should be independent of the temp sensor.

Congratulations on your override installation.

The Mighty Gryphon · « **Reply #4 on:** February 02, 2017, 06:43:46 PM »

Filmcamera, I think the difference is that there are two different circuits for the fan relay. The difference depends on the engine control. On the Jetronic, the fan works off the temperature relay while with the Motronic, the fan is controlled by the engine control unit.

Filmcamera · « **Reply #5 on:** February 02, 2017, 07:17:41 PM »

When I first installed the new loom the fan was working then it stopped and then it became intermittent so I suspect there is a bad connection somewhere.

Living as I do in CR where the average temp is around 78 F all year round I am very happy to have an override switch anyway. On a short ride yesterday the moment I dropped below a sustained 40 mph she started to heat up (to be fair it was 90+ F). The last mile to my house in the hills is a 1 in 5 or so and very bumpy so 15mph 1st gear all the way and even starting at normal temp she is close to boiling by the top of the hill, so as long as I can turn the fan on when I want to I am happy.

Meanwhile I am thinking of opening a mobile hotdog stand so I can cook them as I ride...damn bricks is warm...

pvsager · « **Reply #6 on:** May 27, 2017, 03:23:17 PM »

Hello everyone. First time poster so I hope I am doing this right. I too now have the "fan not coming on by itself problem". What I have done so far is: replace the fan (the brushes were totally melted), check that the wiring from the relay to the fan is fine by jumpering, replaced the temperature switch temp relay with an albeit used but supposedly working one from motolister. It seems that I am no further ahead as my temp light comes on and the fan does not. My question to the forum is should I continue trying to fix this or just go for the manual on/off switch repair- getting frustrated

Martin · « **Reply #7 on:** May 27, 2017, 03:53:12 PM »

Go back to the first posting and test as per RBM's instructions. Once you the OEM system working it is worthwhile to fit an override switch as it reassures you that the fan is working and regular exercise helps stop the fan from seizing.
Regards Martin.

pvsager · « **Reply #8 on:** May 27, 2017, 04:18:58 PM »

Thanks Martin. I actually have the fan able to turn on just not automatically. Is there a popular or best way to wire in a switch? Hope I'm not hijacking this thread hahah

Martin · « **Reply #9 on:** May 27, 2017, 04:42:48 PM »

It is best to start your own thread with problems. There is a search feature on this site to help you locate answers to problems.
http://www.motobrick.com/index.php/topic,2337.msg12885.html#msg12885

Regards Martin.

blackie1 · « **Reply #10 on:** March 08, 2018, 03:59:36 AM »

hi Robert
was just looking at one of your old posts
http://www.motobrick.com/index.php/topic,8295.0.html

when you say "Jumper A2 to 45 will bypass the temp relay and the fan should start. Proves the fan works."

would i do that with something like this (see attached pic)

also , my bike is a K75, in your post were you referring to a k75 or k100 or do they both use the same relay?

thanks in advance
ross

rbm · « **Reply #11 on:** March 08, 2018, 05:27:06 AM »

Hi Ross,

Those instructions in the first post are meant as diagnosis techniques and not permanent modifications. They help you to isolate failing parts so you can repair the cooling system.

On the schematic diagram in the first post, you will see lines in Blue. These lines represent permanent changes to the circuit that you can undertake to install an override switch. WARNING: don't install both circuits; choose only one. IMO, the best one to pick is the one which grounds Pin E.

It would be difficult to use the wire you illustrated with a 1/4" female spade connector at each end to do any of the modifications. The reason is that the existing wiring must remain in place alongside your modification. The solution to this problem is to use a male-to-female spade adapter, pictured below:

blackie1 · « **Reply #12 on:** March 08, 2018, 01:16:12 PM »

yes i only want to diagnose, not modify.

so i remove the relay from the bike
and insert a probe into the socket where pin E would go and then ground the other end of the probe?

rbm · « **Reply #13 on:** March 08, 2018, 05:49:24 PM »

Hi Blackie,

No, please don't remove the relay from the socket. It is required to successfully run this test. Remember that the temperature "relay" is not a relay; it is a complex electronic module. When you ground the "E" input, you are simulating the conditions that would be present if the engine was overheating. The temperature module will sense this low resistance and turn on the fan. If the temperature module were missing, nothing would happen if you tried the test.

In all cases, the temperature module must be present for the diagnosis to work.

thecableguy · « **Reply #14 on:** March 08, 2018, 10:34:20 PM »

"Ground pin E will simulate overheating to the temp relay. The fan should start and the overtemp light illuminate. Proves the temperature relay is functional."

Is this only active when the engine is actually running or will it work to test with the key on? I'm working on wiring my new fan override switch...

Jim

Laitch · « **Reply #15 on:** March 09, 2018, 12:09:12 AM »

Quote from: thecableguy on March 08, 2018, 10:34:20 PM

"Ground pin E will simulate overheating to the temp relay. The fan should start and the overtemp light illuminate. Proves the temperature relay is functional."
Is this only active when the engine is actually running or will it work to test with the key on? I'm working on wiring my new fan override switch...

Read this post.

thecableguy · « **Reply #16 on:** March 09, 2018, 12:37:05 AM »

Sorry, but that post doesn't seem to answer my question. Let me rephrase.

I need someone who has added a bypass switch in the dash as wired in solution#1 in the schematic in the first post in this thread to tell me if the fan will come on with the override if the engine is not running but the key is on/lights on?

I just installed my switch and wired it that way, grounding thru the switch the purple/green wire that goes to pin 'E" on the relay. It does not run the fan with the key in "ON". I've got more of the bike apart right now(tank off) and can't start the engine to test. I'd just like to know if I need to troubleshoot more.

Jim

Inge K. · « **Reply #17 on:** March 09, 2018, 05:42:13 AM »

Quote from: thecableguy on March 08, 2018, 10:34:20 PM

Is this only active when the engine is actually running

Yes,... Because the the electronic components in the fan relay get power from the FI relay.
The FI relay closing its contact only when the starter is turning or the engine is running.

Laitch · « **Reply #18 on:** March 09, 2018, 10:16:21 AM »

No more late nights here for me. :giggles

thecableguy · « **Reply #19 on:** March 09, 2018, 11:43:25 AM »

Yeah, it was late for me too... Wasn't sure if I was getting my point across.

Thanks Inge, that's exactly what I needed to know. Turned the key on, flipped the new bypass switch on, and blipped the start button. Fan spins!!!

Ok, I can now button her up without worrying I had untested wiring...

Thanks!!!
Jim

The Mighty Gryphon · « **Reply #20 on:** March 09, 2018, 12:38:10 PM »

Nice job! :clap:

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Author Topic: Re: Cooling Fan Activation Time Interval (Read 14991 times)