jmlcolorado

Anyone know of a way to test the fan clutch? I noticed a few months ago it the fan seemed to be running more often then normal. Fast forward to this week and the fan is always engaged. 55* outside, AC off, cold start, the fan is screaming.
Is there a relay that opperates the fan after the ECM signle?
I have to change my water pump pretty soon since it has a small leak and id like to tackle the fan clutch too if needed.
Thanks!

papaduck

Unplug the wires that are located on the passenger side near the bottom of the radiator. If the fan still roars then the clutch is bad. You should also be able to spin the fan with the engine off. If not then the clutch is locked up.

jmlcolorado

Perfect! That's exactly what I needed. Fan clutch is stuck engaged. Fan rund screaming full blast at 2000 rpm and it has quite a bit of friction when trying to spin with the truck off. So much so that no mater how hard I try, I can't get it to spin freewheel without my input.

Fan clutch replacement it is.
Thanks for your help!

jmlcolorado

Well, I replaced the fan clutch today. It's doing the same thing. Fan will be engaged with the plug unplugged, and its engaged at first cold start as well
Any ideas as to what to look at next?
That $225 worth of parts didn't fix the issue :/

I took the truck for a 15 minute drive to see if it needed the vicious material to redistribute. AC off, even ran the tuck uphill in third gear at 25 mph and 2200 rpm for about a minute to see if it would cool enough to kill the fan. Still on solid

jmlcolorado

Pulled some codes to see what the truck sees
P0480 Cooling Fan 1 Control Circuit Malfunction (likely because I ran the truck with the connector unplugged.
P0483 Cooling Fan Rationality Check Malfunction (same reasoning as above)
P0237 Turbocharger Boost Sensor A Circuit Low (have always had this since the chip)
P0192 Fuel Rail Pressure Sensor Circuit Low Input - (have always had this one since the chip)
P2509 CM/PCM Power Input Signal Interm. - this one is strange too. I noticed by gauges changed back to their factory color a few days ago. They only do that when I unhook the battery. I'll have to look into this.
P0236 MAP Sens Too Hi Too Long. - another weird one.

I'm still not seeing anything related to cooling other then the fan circuits. A handful of clear starts and these should clear....... Maybe.

06RAM2500

I'll get the reason behind the codes pulled up here. Be just a couple minutes, sit tight.

06RAM2500

P0236 - Map Sensor Too High Too Long
*reason could be the sensor itself or because of other codes. Remove the chip from the truck, erase the codes, and see which ones come back. If the P0236 does, your sensor is bad.

The P0480 is the fan clutch. On your old one, measure the resistance of pins one and two (lock tab on top, top row of pins, w/ 1 and 2 being the furthest right). If the resistance is less than 10 ohms, your clutch is bad. More than 10, got a good spare and it's likely your wiring is damaged on the truck side.

P0483 is either a bad clutch or bad wiring

P2509 Power down data lost error. How old are the batteries, and how corroded are the terminals?

jmlcolorado

Don't know if I've done a MAP sensor on this truck or not. Might have been my 98 so this one could be bad.
On the resistance test, I don't get a reading at all on any setting on the meter. I'm not much of an electronics wizard, had the meter set on 200, then tried the rest at 2000, 20k, 200k and 2000k and read nothing on any of them. If I remember right, it needs to be at 200. I do get 7.5 between pin 1 and 6 though if that means anything

Seems I've had the fan circuit code since at least February since I re read one of my old threads and saw that same code was there when I checked for another problem.


I'm thinking I might have a wiring issue somewhere. I'm thinking of cutting pin 6 out since that's the power lead and see what happens. (Edit: now that I think about it, if the fan is running with the connector unplugged, this still won't do anything. :/ )

Batteries are less then a year. I had to replace both power leads as they were so far gone, they almost burned up everything in the truck. Was loosing the passenger side battery and the alternator was trying to compensate and spiking voltages to extreme levels.

jmlcolorado

Okay, lets go this route. The fan is controled by the ECM right? So If I brought the truck up to operating temps, then unplug the fan connector while its running, I should be able to check voltage between a couple terminals right? How bout if I check those two terminals when the engine is cold? I should see no signal voltage.
Lets assume I see signal voltage when the engine is cold, AND when the engine is warm. What are the triggers that the ECM see's that signals the fan to engage? I assume obviously engine temp, AC power, is there anything else?
Does the thermostat has a sensor on it that signals the fan? Wondering if maybe the thermostat cold be stuck in "I'm freakin hot" mode which would tell the ECM to engage the fan all the time?

Based off the below pinout, which wires do I test for signal? I assume + is pin 6 and the single wire would be pin 1 which would be ground right?
So with a cold engine, I should see zero voltage between 1 and 6, and on a hot engine I should see voltage between 1 and 6 right?

VISTRONIC FAN DRIVE (DIESEL) - DK GRAY 6 WAY

CAV CIRCUIT FUNCTION
1 K160 18BR/OR PARK LOCKOUT SOLENOID CONTROL
2 K900 18DB/DG (EARLY BUILD) SENSOR GROUND
2 K690 18DG/YL (LATE BUILD) SENSOR GROUND
3 K161 18BR/LB FAN SPEED SENSOR
4 - -
5 F856 18YL/PK (EARLY BUILD) 5 VOLT SUPPLY
5 K668 18LG (LATE BUILD) 5 VOLT SUPPLY
6 F504 20GY/PK FUSED IGNITION SWITCH OUTPUT (RUN)

06RAM2500

One other thing you can do is have the dealer take a look. It's not going to be super expensive, but they can plug their scan tool in and find out what the issue is relatively fast. If you do decide to go there, make sure you remove your chip completely.

jmlcolorado

Yeah I was hoping to avoid that route, but if I can't figure it out, I might let them hook up their scanner. I'll have to remove the chip for a few days since it throws a couple codes when it's hooked up.

jmlcolorado

Well, I thought the problem was fixed. Fan seemed to stop running, then we rolled into winter. I never noticed the fan kick on even in defrost. I thought nothing about it.
The past few days it has been a bit warmer out. 65-70 so I kicked on the ax a few times. I noticed the AC would start blowing cold when sitting still. I figured that was a separate issue. Then today I caught up in some traffic. Sat still and hardly moved for about 20 minutes. It was about 75 out this round. AC blowing nice and hot.
Then I noticed the temp rising. I was steady at 200*, then it got up to about 215-220. No fan at all
Well crap, here we go again.
I tried testing pins 1 and 2 and got nothing.
This is the newer fan clutch, and the "test" shows its okay.
SO, I jumped pin 1 to ground, and the fan kicked on.
The only code I'm getting now is 0408 (think that's it).
I feel like the ECM has gotten confused and doesn't know when to send and not send a signal.

nvr-enuf

Do you have a tranny temp gauge?

jmlcolorado

No trans gauge. I've got the NV5600.

jmlcolorado

Still no change in the fan. I wired in a switch temporally to turn on the fan when I see its getting too hot.
Guess its off to the dealer for me