Oil temp light blinks intermittently even when cold.

[Cutlass52 8]

Have disconnected the wire from the temp sensor and grounded it. The temp light comes on and the fan runs. Looking for help diagnosing the problem. Thanks

[AKATV 717]

(He is having issue with temp light blinking on and off even when stone cold-has replaced temp sensor already)

told to him to cook the FCU at 450 degrees in oven for 7-8 minutes to try and bring it back

If not, advised to replace with good (used) OEM FCU

 

[toodeep 1,725]

If it's a 400/450 Foreman it sounds like the alarm/fan control unit. It can be with any machine but those models are very common for me to have this issue.

[Goober 1,549]

what year n model?
 

My 450S was doing exactly what you’re seeing. Fan Control Unit. Your oil temp sensor may also fail resistance test too.

 

you can try baking your FCU in a 200F oven for 3 hours. May revive it for a month or two.

 

use OEM parts finder at Rocky Mountain atv and Partzilla. Use service manual to troubleshoot system—oil cooling system diagnostics 

Edited February 9, 2022 by Goober

[Cutlass52 8]

Thanks all for the advice. I have cooked it per instructions from AKATV. It has cooled and been removed from my wife's oven. No evidence left. I will try it tomorrow and see what happens. 

[jeepwm69 6,827]

11 hours ago, Cutlass52 said:

Thanks all for the advice. I have cooked it per instructions from AKATV. It has cooled and been removed from my wife's oven. No evidence left. I will try it tomorrow and see what happens. 

 

Smart man! 

 

Took me a while to get used to having a woman in the house again when I remarried.

 

I quickly learned no engine/gun parts in the oven, no  ATV/Jeep parts in the dishwasher, and when you scratch up her coffee table putting together a Foreman bottom end together on it she gets really ticked off.

[Goober 1,549]

After i butchered a goat kid in the kitchen i was told no more wee ones. Antelope, deer and Elk are OK, but only in the garage.

[Cutlass52 8]

Thanks all for the advice. I have cooked it per instructions from AKATV. It has cooled and been removed from my wife's oven. No evidence left. I will try it tomorrow and see what happens. 

[Cutlass52 8]

Installed the fan control module after cooking it per instructions from AKATV. Have driven it four miles and the light never came on or blinked. Seems to be working good. Just hope it continues. Thanks to all you guys for your advice.

[AKATV 717]

Thanks for the follow up glad to hear it all worked out for you

Hope to see you around here on the formum take care

[Goober 1,549]

Very good. The reviving may last a day a month—mine lasted 6 months. Gave me a chance to shop for a new one

[AKATV 717]

15 hours ago, Goober said:

what year n model?
 

My 450S was doing exactly what you’re seeing. Fan Control Unit. Your oil temp sensor may also fail resistance test too.

 

you can try baking your FCU in a 200F oven for 3 hours. May revive it for a month or two.

 

use OEM parts finder at Rocky Mountain atv and Partzilla. Use service manual to troubleshoot system—oil cooling system diagnostics 

 

I wanted to clarify something here and to dispel some bad information that s out there

 

There are some threads out there that mention putting these in the oven to "dry them out" and get them working

 

There is absolutely no way that moisture can get inside these modules. The circuit board inside is potted (sealed) in epoxy resin

So, thinking you are ""drying it out" when putting it in the oven is not really whats going on

Putting in in oven at a low temperature like 200° for a few hours isn’t really gonna do anything but tick off the wife

If it works after that, all you’ve done is probably expand a cracked joint that’ll make a temporary connection until it separates again and goes back to the original failure problem- hence why this seems to only be a temporary fix for some

 

The fix is to put this in the oven at a temperature that will melt solder and will re-flow the circuit boards bad connection's to fix what the actual problem is, which is basically a broken or cracked solder joint on the circuit board due to either a cold (bad) solder joint at the factory or the heat and vibration after 20 years eventually cracking a solder joint

I have found a 450° for 7 to 8 minutes seems to be the sweet spot -it won’t fix them every time but I’ve had a very high success rate probably better than 90% through the years on at least 50 or so of these modules

As I have previously mentioned, some of these are still working 15 years after the fact

I hate to see someone try and just warm one up in an oven at a low 200 degrees and have it not work, or temporarily work and then go out and buy another OEM one when they could possibly fix theirs with proper knowledge of what occurring and a little higher temperature

 

This will work on the CDI boxes as well, that is why they will spark when you knock or tap on them while cranking, you are closing up

the bad solder connection inside when you tap on it. 

 

Its not a 100% fix, as some modules go bad for other reasons as well -but in MY experience when they are fixed, they are fixed for a good long while. You might have to do it a second time possibly if first time does not work, but if it does not fix it after that just toss it and get another

 

 

Edited February 9, 2022 by AKATV

[_Wilson_™ 5,985]

did i not say (ALONG TIME AGO) some of these members need professional help......... naw scratch that idea........ it won't do any good. 

[jeepwm69 6,827]

1 hour ago, AKATV said:

 

I wanted to clarify something here and to dispel some bad information that s out there

 

There are some threads out there that mention putting these in the oven to "dry them out" and get them working

 

There is absolutely no way that moisture can get inside these modules. The circuit board inside is potted (sealed) in epoxy resin

So, thinking you are ""drying it out" when putting it in the oven is not really whats going on

Putting in in oven at a low temperature like 200° for a few hours isn’t really gonna do anything but tick off the wife

If it works after that, all you’ve done is probably expand a cracked joint that’ll make a temporary connection until it separates again and goes back to the original failure problem- hence why this seems to only be a temporary fix for some

 

The fix is to put this in the oven at a temperature that will melt solder and will re-flow the circuit boards bad connection's to fix what the actual problem is, which is basically a broken or cracked solder joint on the circuit board due to either a cold (bad) solder joint at the factory or the heat and vibration after 20 years eventually cracking a solder joint

I have found a 450° for 7 to 8 minutes seems to be the sweet spot -it won’t fix them every time but I’ve had a very high success rate probably better than 90% through the years on at least 50 or so of these modules

As I have previously mentioned, some of these are still working 15 years after the fact

I hate to see someone try and just warm one up in an oven at a low 200 degrees and have it not work, or temporarily work and then go out and buy another OEM one when they could possibly fix theirs with proper knowledge of what occurring and a little higher temperature

 

This will work on the CDI boxes as well, that is why they will spark when you knock or tap on them while cranking, you are closing up

the bad solder connection inside when you tap on it. 

 

Its not a 100% fix, as some modules go bad for other reasons as well -but in MY experience when they are fixed, they are fixed for a good long while. You might have to do it a second time possibly if first time does not work, but if it does not fix it after that just toss it and get another

 

 

Think that would fix an ECU for a 500 that no longer turns the fan on?

[AKATV 717]

Not sure -through the years I’ve only tried the fan control modules and the CDI modules from the 300 400 450s

It seemed to me that they just combined the CDI and Fan controller when they made the 500 module

so it kind of sucked, as you couldn't replace just the one failed controller plus made it (even) more expensive

Is yours the ECU for the electronic shift model or foot shift model?

I would say if you have troubleshot the fan not coming on back to the ECU then it would be worth a shot

I guess you’d have to weigh the risk out

In my experience I’ve never made anything worse …but there’s always that chance lol

Edited February 9, 2022 by AKATV

[jeepwm69 6,827]

I have an ES that was bad.  Sold the bike so it’s just sitting.

 

Want to dissect it?  No use to me.  I’d love to see the innards and what caused the fan to stop working, as it seems to be fairly common on these 500’s I have

[toodeep 1,725]

I haven't had any issues with the fan part on the 500's. I have saved a few power steering control units to try to bake and see if they would come back to life. They are some $$$ and a power steering model without power steering sucks, big time.

[Cutlass52 8]

Thanks for the offer to dissect the module. I really don't have time. I have too many irons in fire now. Have already spent more time than I intended working on my 450 and still have things I need to do to it.

[jeepwm69 6,827]

On 2/10/2022 at 7:33 AM, Cutlass52 said:

Thanks for the offer to dissect the module. I really don't have time. I have too many irons in fire now. Have already spent more time than I intended working on my 450 and still have things I need to do to it.

 

That was directed at AKATV.  He's not busy at all repairing the meters everyone is coming here to get fixed...lol

 

 

[NB Floyd 29]

Could someone post a picture of the FCU and where it is located ?

 

About to try the baking method.  

 

Thanks.  

[shadetree 5,501]

2 hours ago, NB Floyd said:

Could someone post a picture of the FCU and where it is located ?

 

About to try the baking method.  

 

Thanks.  

most fan control units are located in the front, right under the fender, directly under the handle bars, they are in a rubber boot, connected to the frame in the center, they have tricky tabs that you have to press in order to get them apart, and off the frame.

[AKATV 717]

Here’s a pretty poor picture but it gives you a general idea I stuck my phone up underneath and blindly snapped a photo you can see the CDI on the left and the fan controller with the green plugs on the right I don’t know if you have an electric shift model or not but you can see the electric shift module ECU down below as well,like Shadetree said, this is basically just front center underneath your fender mounted up top