Starting a new thread for this problem.

Bus started driving hot yesterdat. EOT was 231 when I noticed. Hadn't checked sooner because I hadn't heard the fan come on.

I slowed to 55 and got it back in the mid teens..struggled with it the rest of the day, bouncing up to 227 and down to 215 as I went up and down hills. After the sun went down, it stabilized back in 212.

All that time, even with ECT up to 216, I never head the fan kick into high gear. I figured it was the fan connector wires again, the ones that burnt and I've tried to patch back up. xhecked them this morning, the burned wires on the harness side are so close to the connector that theres nothing left coming out of the connector to splice to.

I separated them where the liquid tape had them stuck together and hoped that was the issue. Didnt know the pin outs.

Started driving and for several hours and a couple hundred miles, it drove great. EOT stayed between 205-211, up and down hills driving 60mph, no problem. Still never heard the high speed fan, but at those temps that's normal.

Then, the sun starts warming up, from overnight low of 60 up to the mid-80s. And the truck temps went up accordingly. I drove most of the afternoon with EOT from 220-228, usually in the middle.

Yesterday, I could get it back in the teens slowing down, but not so much today. I pulled over for 30-40mins, it was at 203 when I started up, and was quickly back in the 220s.

Heres the kicker: while I thought I heard the fan at low level at times, I wasnt sure (noisy truck bad hearing), but definitely not high speed - until a few minutes ago, after I'd stopped for a few mins, so truck was cooler, and also at low speed, like it does sometimes after idling at a red light.

So, that blows my theory that it's a shorted power wire keeping it from working at all.

Any theories? I am doing damage driving in the 220s for so long? Maybe I need to direct wire the fan to bypass the connector? Or maybe just bypass some of the wires?

 

The famous Blue wire Mod. I have it in my truck don't never use it. But it's there. It's a good thought might help.

 

Isn’t there a sensor that has a fan speed output? Confirm if it is working or not?

 

There is in torque pro and Forscan

 

Thanks guys. I just found the fan speed PID and will see what it tells me tomorrow. How is it supposed to act? What is the top speed?

I have the Blue wire model on my truck. So much easier to do on the Fseries. Is it a solid blue wire or one with a blue stripe? IIRC, I'm just supposed to run a 12v wire to bisect the blue wire w/o cutting its connection to the fan connector. Put a switch in your new wire so I can turn the 12v on and of, right?

My concern is that all the wires are burnt right at the connector, theres no good wire in front of the burn to bisect. I'd have to bisect further up the pigtail, which does no good.

So I'd have to go to the other side of the connector. But the wires are all inside a sleeve tucked into the plastic bracket. It can be done, but I wonder if it's the same blue wire on that side?

 

The new code that popped up i3 p0113. Not sure if it happened while I had the air cleaner off. Prolly need to clear it and see if it resets.

 

A good working cooling system is essential for 6.0s to avoid heads/headgasket issues, so my experience. At 99*C / 210*F I switch the fan to maximum rpms. Mostly this is on mountain passes or long uphill drives (1 eye always on ECT, EOT and coolant pressure). But I am always on the road with a heavy vehicle (RV).

 

You ground the fan excitation circuit. You put 12v to that would not be a good thing.

 

yes, I´m switching the ground

 

I was telling Ron.

 

OK, I got the speed sensor data. When I first started out this morning, it was +/- 1200rpm. After about 30 miles that was down to 1100, later it stayed under 1000 for most the day. I think that was reflecting the speed I was driving - as I slowed down, the fan slowed down.

But, I also have seen it kick up - when the coolant hit 213.8, the fan kicked in for 10-15 seconds. First time, it went as high as 2200rpm, every time since then, it only goes up to about 1800. But, 10-15 seconds isn't enough. It knocks the coolant back to 212, for a few minutes. It did kick into high RPM once, when the coolant hit 215, got up to about 2500rpm and sounded like it usually does at high speed. But, again, it only lasted a few seconds, not long enough to matter.

Right as I quit tonight, it also kicked in a few times as I was driving slowly in city traffic, like it does sometimes when you first start out from a red light.

The truck did like yesterday - when I started out this morning, it ran great. All the way across New Mexico, EOT was in the low teens. It'd go up to maybe 218 going up a hill, but would cool back down. But, that was mostly flat land.

Then, I got to AZ, and there was a long incline over many miles, and you could just watch the EOT tick up a couple of tenths of a degree at a time. Just when I was about to pull over, I reached the crest and started downhill. Got all the way back to 206EOT and stayed that way for another hour or so. Then, it was getting hot out, and the rest of the afternoon, I struggled to keep it in the low 220s. Driving 45-50mph.

It's like the truck drives great until elevation makes it get hot up to a point that it needs the fan to cool down, without the fan, it never cools down again. I literally almost have to pull over and let it cool down. By the time I got to Phoenix, it wouldn't cool down even going 30mph around city traffic and flat land; stayed around 221.

But, importantly, it's 102 degrees in Phoenix today. I get the feeling that if I were driving in 50-60 degree weather, the truck would drive normal. But because its been 80+ this whole trip, it needs that fan to work.

Soooo, I've tried mess with the fan again this morning. My dilemma is that if I mess with it too long, I'm using up the cool part of the day when it would drive fine. I cut into the light blue wire on the harness side to expose some bare wire, then took a length of wire and wrapped the bare end around that cut I made. I started the truck and tried to ground the other end of that wire around the engine compartment and nothing happened. I remembered reading an old thread here in which someone said that wouldn't work with the truck just idling because the engine doesn't make enough heat for the PCM to send power to the fan. So, needing to drive and it being cool morning, I took off with the bare end of the wire in the cab. After the truck warmed up, I tried grounding it to metal in the cab (it has a heavy steel mounting stand for the lever that opens the swing doors), and still nothing.

Not sure if my splice is no good, if I got the wrong wire in the connector, if I wasn't grounded it properly, or ??? At the time, I even figured that there was no way it could work, thinking that the connector wires were burnt through was why the fan wasn't working. If they're burnt through, then grounding them would do nothing.

However, now that I've seen that the fan does actually kick in, I'm thinking that means that all the wires in the connector are intact. So, why does the fan only run a few seconds?

Does that behavior suggest that maybe one wire is burnt through? Maybe I need to splice that wire directly into both sides of the connector, to bypass the shorted out section. have to go to the other side of the connector because the burnt shorted out spot is right up next to the harness-side connector - there's no good wire left to splice to.

This is crazy - my truck is running great, but I might blow it up just because I can't get the dang fan to run. And, I can't get a pigtail for that connector out here on the road. I got no choice but to splice, but some of the burnt wires don't have much left to splice to. Before I tear into it, and potentially get really stuck out here, I wonder whether it could be something else? Maybe the fan clutch went bad? Or the sensor?

Tomorrow is my worst day. West from Phoenix is desert, then mountains higher than then ones in AZ before I get to LA. I might make it past the desert if I start out early - the entire distance is less than 400 miles - but not if I stop to work on it in the morning.

Any suggestions?

 

>>>I tried grounding it to metal in the cab (it has a heavy steel mounting stand for the lever that opens the swing doors), and still nothing

If it's a good ground.

Fan kick in doesn't happen instantaniously, it can take a little while.

 

Yes, the one in my truck takes a few seconds.

I really need help with this one. If I mess with those wires and can't get them fixed, I'm here for days waiting for a pigtail to arrive from China. Even that is no sure thing - these Eseries are a pain to get to those wires.

Thinking to myself...

1. the PCM can command the fan on, and at various speeds. I have seen that. Does that mean that all 5 wires have connectivity from the harness through the connector to the fan? If so, then a) the blue wire mod should work, and b) that's my best/easiest/quickest solution.

2. I have also seen that the PCM only commands the fan on for a few seconds, at all of the increased speeds (I'm assuming that there's a base RPM - that low number I see in the data that equates to vehicle speed). Why is that? If I can't be sure that the 5 wires have connectivity, could one or more of them being broken cause these short commands? Is another solution that I need to splice one wire to bypass the original burnt/shorted area, maybe not the blue wire? If so, I have to bypass the connector too - there's no wire left coming out of the connector harness-side to bypass to. And that means tearing into what may be a perfectly fine fan clutch harness.

3. Or, maybe the 5 wires are connected, and everything is working fine, except that the fan clutch is broken. The PCM is commanding high RPM, and the clutch just can't do it. That means all this risky splicing won't solve anything - probably cause many more problems. I hand spun the fan, and it doesn't have up/down in/out movement.

I gotta make a choice tonight. I can't blow this truck up over a silly fan.

 

Put in the snow plow fan clutch an the blue wire solution. Like Jack mentioned it takes a few seconds until you hear the fan noise (driving, not idling)

 

Thx, HW, but I'm trying to rig something to make it home. Would rather not change out the clutch on the side of the road.

I dont want to mess with these flimsy wires if the blue wire mod wont work because one or more wires arent even conducting through the connector to the fan.

Also, will the fan even operate at idle - to test my blue wire mod - or do I have to drive it to WOT? I hate to do that because then the truck is too hot to work on.