DeTaylor

I have tracked down the issue to be a bad connection in these connectors. Does anyone know how these come apart? I’m 15 finger pricks and 3 beverages in with no luck. 

6 minutes ago, Goober said:

Maybe you have a pin loose in the connector 

Remove the FCU and use a multimeter to test which it is

Can’t believe I didn’t even think of this. Will definitely do this tomorrow. Thanks!

So I’m still chasing down my overheating issue. Starting to think it’s all electrical. I hard wired my fan to do some testing and here is what I’m finding. Fan does not run unless I apply downward pressure to the harness connectors on the FCU. Never seen anything like this. I have two different FCUs and both are doing the same thing.

i tried putting a little dielectric grease in there to see if it was potentially a bad connection and it made no difference. 
 

Thoughts??

video attached. 

@Fishfiles I’ll give it a look. I would guess that this would be negated since everything works when I ground out the wire from the backside of that harness. 

That’s exactly what I was worried about. Thank you for relieving that stress! Going in the oven now 

2 minutes ago, AKATV said:

  Reveal hidden contents

 

You don’t need to wrap it up in tinfoil  just place it with the green plug side up on a pie pan or piece of aluminum foil and don’t move it until it cools down

When you’re talking about green clips are you talking about the female plug that’s attached to the module itself?

Female plug ends - Yes that is correct. I’ll remove the wrapping. 

@AKATV here we go! Just to verify, the green plastic clips stay on? 

1 minute ago, AKATV said:

Have you tried baking your fan control unit at 450 for 7-8 minutes and see if the problem goes away?

Pretty common to have oil temperature control lights on and off with a faulty fan control unit

I was avoiding this, but I think this is the next test! 

Well my mysterious red light of doom continues. I was paranoid that I still had an issue when my light flashed at me the other day. Ordered a oil temp sensor from PSN and now the light is on pretty consistently. The odd part - my fan still isn’t kicking on. As stated above, my fan does turn on if I ground out the oil temp sensor wire.

i don’t have any clue where to turn next. 
 

not sure if it matters - the light was not on right away. I had to hit a few bumps first (wiring somewhere???) and then the light kicked on. 

1 minute ago, Fishfiles said:

 

 

Do you know about keeping the oil cooler fins cleaned out , they will get clogged up with mud pretty quick , depending on your riding conditions , sqampy woods , sounds like something I would do 

Yessir. After reading through this thread that was the first thing I cleaned up. They weren’t completely clogged but there was a bit of dirt in there. 

14 minutes ago, Goober said:

Keep it! You may need it and now you have a spare!

If no one wants it I’ll hold onto it. Just trying to help someone else out if I can. 

1 hour ago, jeepwm69 said:

Points to your fan sensor being bad.

when the old temperature reaches a certain point, the sensor grounds that wire cutting the fan on.

 

That said, if you have top end issues that are causing it to get hot really quickly, the oil temp sensor will not cut the fan on because all of the heat is on the top end.

 

I had a 500 with a bad oil pump, and the top end got scorching hot really fast because there was no oil going to the top end. The fan never came on because the oil in the bottom of the crank case was not hot.

 

Does that make sense?

 

Pretty sure the issue was a loose sensor. It occurred to me that this started after running through swampy woods last week. Plug was loose and dirty. Cleaned it up, took it for a hard 4 miles around the block and back through the woods for 15 min - no light at all. 
 

i am curious though if I should still check the oil pump. Got me worried now 

I have an extra oem CDI box. I bought a new one from PSN but the actual culprit was the voltage regulator. Swapped out the parts and left them since it was already installed. $15 (includes shipping) to whoever wants it. 

@AKATV is putting in the work! 
 

also incredibly happy with the work he did for me!! 

1 minute ago, jeepwm69 said:

Points to your fan sensor being bad.

when the old temperature reaches a certain point, the sensor grounds that wire cutting the fan on.

 

That said, if you have top end issues that are causing it to get hot really quickly, the oil temp sensor will not cut the fan on because all of the heat is on the top end.

 

I had a 500 with a bad oil pump, and the top end got scorching hot really fast because there was no oil going to the top end. The fan never came on because the oil in the bottom of the crank case was not hot.

 

Does that make sense?

 

Makes sense, atv doesn’t seem to be getting excessively hot in any way. Think the fan sensor may be the culprit. Might also explain the light being dim and coming and going. 

1 hour ago, AKATV said:

 

also if you ground the blue single wire behind the right rear fender either to the frame or to the negative side of the battery and the fan does not come on it’s also generally the fan control

 

So I grounded it and the fan did in fact come on. What does this mean then? Appreciate all the help!

3 hours ago, jeepwm69 said:

 

Single wire going to the back of the engine, goes onto the temp sensor. 

 

Pull that wire off, and ground it on the engine with the key on.  Fan should come on at that point, along with the temp light

ignore this - figured it out 
 

Another dumb question. Do you pull the wire off the sensor side or the fender side? Looks like someone has done some custom wiring on the fender side. 

1 minute ago, AKATV said:

Nope -just unplug it, put it on a piece of tinfoil or a pie tin with the plug side facing up preheat the oven put it in there for 7-8 minutes and let it cool down without touching it and give it a try

sometimes it takes a second cooking but it’s definitely worth a shot if it’s not working to begin with as you have to get a new one anyways right?

I’ve had very good luck with this -let us know how you make out

it helps to troubleshoot everything else first just to make sure

make sure your fan is functional by applying 12 V directly to it

You can test the temperature sensor on the bottom of the engine by heating it up and checking the resistance as per the manual as well

what I have found through the years for the most part is if you turn your key on and the red light for the temperature does not come on for a second or two and then go out, it’s generally the fan control unit

also if you ground the blue single wire behind the right rear fender either to the frame or to the negative side of the battery and the fan does not come on it’s also generally the fan control

At that point, I’ll just bake the fan control unit and if it doesn’t fix it after the second bake, I will replace it but I generally find it works better than 80% of the time with some of them still continuing to work many many years down the road

 

Looks like I know what I’m doing tonight. Thank you so much!

On 5/18/2022 at 10:34 AM, AKATV said:

Was key on when you jumped wire?

it has to be on for the fan to come on

If so, you can put FCU in oven @ 450 for

7-8 minutes- it will bring them back a lot of times  as failed internal solder joints causes most issues

Also, make sure fan is good by powering up directly

 

Might be a dumb question but do I have to prep the FCU in anyway before exposing it to 450 degrees of fury? 

8 minutes ago, jeepwm69 said:

 

That's usually backfeeding/wire grounding out somewhere (the dim light)

 

Have the same issue on my buddy's 450 I'm working on now.  I haven't had time to dig further into it after hooking up a battery and finding both Neutral and Reverse lights are both on at the same time (but they're dim as you mention)

Oddly enough the reverse and neutral lights are working just fine. Even the temp light works great on start up. Only when driving does it seem dim. 
 

I’ll ground it out and see what happens. I really don’t think the fan will turn on lol I’ve checked quite a few times and never seen it move. 

16 minutes ago, Bossdaddy said:

I wish I could help. There are some guys on here that can get you started. It sounds like a wiring problem or bad sensor, they will help you out, good luck.

Without a doubt. Great group of knowledgeable guys. 

I’m also facing over heating now. Red light come and goes pretty frequently the past week. Does the light get brighter as the temp gets hotter? My light, when lit, seems to be fairly dull but is nice and bright at start up. The light also goes away but then comes back shortly after (all in one drive). 
 

Going to start by cleaning the oil cooler and then start messing with the fan - I have never seen it spin but just now getting the overheat issue. 

20 minutes ago, Fishfiles said:

Almost?   We can improve on that!   What’s up?  

Sometimes it’s 2 cranks lol I’m not concerned. More concerned that she is starting to overheat. Fan isn’t spinning now.. always something. 

Problem was actually the starter and solenoid. Ended up replacing both. Once again PSN came in clutch with the oem solenoid for $7. Atv fires up first crank almost every time now. 

18 minutes ago, shadetree said:

tells me the starter is bad. either worn brushes ?, or bad armature ?, either way, the starter needs to be replaced, for what starter brushes cost ?, its easier, faster just to buy a starter from D&B electrical, be done with it.

For $60 I completely agree. Starter ordered from D&B. Thank you for the company tip! Lots of parts that may come in handy in the future.