Community Forums

Ballma · 12-07-2021, 07:13 AM

Just installed a new OEM fan clutch on 2008 Cummins ISB engine, ran 2 1/2 hours at the shop and I drove it another 30 minutes home with no issues. I started backing down the driveway putting the unit in my shop and noticed the temperature going up. Went behind the unit no air coming out of the radiator, look at the fan and it was not turning. I shutoff the engine waited 10 minutes started it up went behind the unit air was moving again. I called Freightliner where I purchased the clutch they said they never had problems.
I called Horton to speak with one of the techs about the problem but the tech could not answer my question so they sent me to the engineer. I explained the issue to him and he ask if I install the upgraded speed control pin 995595 I told him I did not even know about the upgrade. He explained that the speed control keeps the fan turning about 500 rpm when in the disengage mode to keep the fluid in the reservoir.
Has anyone installed this upgrade and did it take care of the intermittent problem?

Toribk · 12-08-2021, 03:33 AM

Ballma,

What was the reason or symptoms that you were experiencing which resulted in having the original Horton fan clutch replaced?

The reason I ask is that if the originally installed OEM fan clutched worked properly since 2008.....and if Freightliner installed the identical fan clutch and wiring harness, the fan should work as it did before without the upgraded kit.....make sense?

With that being said, perhaps their is another issue, possibly electrical, that is preventing the signal to the clutch controller at idle?

Just thinking out loud.

Ballma · 12-08-2021, 05:53 AM

The original finally wore out, when I would start the engine you would not get that burst of air coming from the fan until the ECM sends 12 volts to the clutch, it would just heat up with the fuse in or out and you could turn the fan blade with very little resistance. I purchased the clutch from Freightliner and know they have an issue with these Horton clutches.
I agree with you the old one worked without a speed controller this one should also, that is why I called Horton direct. The way this clutch works is the ECM sends 12 volts to disengage and remove 12 volts to engage around 200 degrees. I checked the output with a meter and the ECM is working correctly so next step is to pull the fuse and drive the unit with the clutch fully engage and see if disengages before installing the speed control.
Thanks for the comments

Toribk · 12-08-2021, 03:59 PM

That is how mine works on my 2012 Cummins ISC 8.3L, but kicks into high right at 210° to bring the temperature back.down if the need arises.

We have had a number of Horton fan clutch issues in our Discovery group and often the first sign of failure is the fan runs on high continously from start-up.

So far, mine has worked as designed

I'm definitely interested in what you eventually find out.

Thanks!

basketball · 12-19-2021, 08:19 AM

The fan logic in the ecm has to be set up correctly to send 12 volts to the Horton fan to turn on or turn off clutch fan. My 6.7 cummins (2007.5) is set up in logic to remove 12 volts and fan goes into high speed.
Had ecm upgraded to latest software and the fan logic was wrong. The new software applied 12 volts to lock fan on high speed. Check voltage at fan fuse when engine is cool. Should have 12 volts when cool, no voltage when engine is hot(fan should go to high speed) Hard to fan speed when driving up grade!!!
Run 2 wires,one from the source of the 12 volts (fuse box,fan relay fuse) and 1 return from the switch to the other side of the fuse. When engine is cool the light should light, when it is hot the light should not light.(12v has been removed from fan relay via the ecm. Will have to have a ground from where the switch is located for light to light.
You can buy 2 wire plugs that replace the fuse and have an inline fuse in line. This makes for easy connection to fuse box to add a fan switch in cab.

Now you can see if the Horton fan is in high speed or low speed. Light on LOW SPEED, Light off HIGH SPEED. Now you can see if the ECM is working correctly.

Ballma · 12-20-2021, 06:21 AM

Quote:

Originally Posted by basketball

The fan logic in the ecm has to be set up correctly to send 12 volts to the Horton fan to turn on or turn off clutch fan. My 6.7 cummins (2007.5) is set up in logic to remove 12 volts and fan goes into high speed.
Had ecm upgraded to latest software and the fan logic was wrong. The new software applied 12 volts to lock fan on high speed. Check voltage at fan fuse when engine is cool. Should have 12 volts when cool, no voltage when engine is hot(fan should go to high speed) Hard to fan speed when driving up grade!!!
Run 2 wires,one from the source of the 12 volts (fuse box,fan relay fuse) and 1 return from the switch to the other side of the fuse. When engine is cool the light should light, when it is hot the light should not light.(12v has been removed from fan relay via the ecm. Will have to have a ground from where the switch is located for light to light.
You can buy 2 wire plugs that replace the fuse and have an inline fuse in line. This makes for easy connection to fuse box to add a fan switch in cab.

Now you can see if the Horton fan is in high speed or low speed. Light on LOW SPEED, Light off HIGH SPEED. Now you can see if the ECM is working correctly.

Do you have a relay on yours?
I have a 5 amp fuse without a relay. I pulled the fuse and the fan remained in lockup the entire time I drove the unit the verify the new clutch was not bad. I think the Horton engineer may be right about the speed control to keep the fan above 500 rpm while disengaged, this keeps the fluid from drawing out of the chamber in the clutch. I have a speed control on order, but has a 56 day lead time.
I will post if the controller fixed the issue with the new clutch.
Thanks

Wild Card · 12-20-2021, 07:10 PM

Quote:

Originally Posted by Ballma

Do you have a relay on yours?
I have a 5 amp fuse without a relay. I pulled the fuse and the fan remained in lockup the entire time I drove the unit the verify the new clutch was not bad. I think the Horton engineer may be right about the speed control to keep the fan above 500 rpm while disengaged, this keeps the fluid from drawing out of the chamber in the clutch. I have a speed control on order, but has a 56 day lead time.
I will post if the controller fixed the issue with the new clutch.
Thanks

Are you sure you don't have a relay? Engineering wise I can't see them using that much amperage to control the fan via the ecm.

Ballma · 12-21-2021, 05:21 AM

Quote:

Originally Posted by Wild Card

Are you sure you don't have a relay? Engineering wise I can't see them using that much amperage to control the fan via the ecm.

I spoke to Freightliner twice about where the relay was located and about getting the electrical drawing for the fan clutch circuit. two different people looked up my chassis using the Vin stating I have no relay, the wires run direct from the ECM to 5 amp fuse to the clutch.

basketball · 12-21-2021, 08:30 AM

Yes I have a relay. On the control board, beside fuse.

RichKimball · 12-21-2021, 10:28 AM

Quote:

Originally Posted by Ballma

I spoke to Freightliner twice about where the relay was located and about getting the electrical drawing for the fan clutch circuit. two different people looked up my chassis using the Vin stating I have no relay, the wires run direct from the ECM to 5 amp fuse to the clutch.

I have this diagram that I was referred to previously.

Freightliner Fan Clutch wiring.pdf

caribbeansk · 03-06-2022, 10:48 AM

Im in the same boat. random overheat, go out back, no fan over the radiator. install guard dog, still has intermittent overheat, each time I pull, over walk out back, and no fans over radiator. usually a restart remedies the situation.

Install new clutch fan, does it even more often, I usually just pull the 5 amp fuse and it cools right down, fans kick right in. Very frustrating. Im going to look at the egr valve while Im at it. I guess it could be a pin on a connector. Freightliner said they cant find anything wrong

Ballma · 03-07-2022, 12:00 PM

Have you spoke with Horton?
I am still waiting on a speed controller they are still waiting on chips.

Ballma · 03-07-2022, 06:33 PM

My next step is source Engineering inc fixed fan no clutch.
I spoke to the engineer about HP draw and they said it is a low pitch and will use less HP

Ballma · 05-05-2022, 09:46 AM

Quote:

Originally Posted by Ballma

Just installed a new OEM fan clutch on 2008 Cummins ISB engine, ran 2 1/2 hours at the shop and I drove it another 30 minutes home with no issues. I started backing down the driveway putting the unit in my shop and noticed the temperature going up. Went behind the unit no air coming out of the radiator, look at the fan and it was not turning. I shutoff the engine waited 10 minutes started it up went behind the unit air was moving again. I called Freightliner where I purchased the clutch they said they never had problems.
I called Horton to speak with one of the techs about the problem but the tech could not answer my question so they sent me to the engineer. I explained the issue to him and he ask if I install the upgraded speed control pin 995595 I told him I did not even know about the upgrade. He explained that the speed control keeps the fan turning about 500 rpm when in the disengage mode to keep the fluid in the reservoir.
Has anyone installed this upgrade and did it take care of the intermittent problem?

Just got the call my speed controller has made it in to my Freightliner dealer after 5 months.