Fan Clutch Troubleshooting

[JStankus]

Been dealing with my fan clutch not working as it should for a bit now. With it being hotter here in Texas than in Phoenix today it is a bit of pain to have the AC quit working in stop and go traffic.



I was able to borrow a multimeter from my brother to do a couple of checks.

1) wires look intact for the circuit (no wire eating as is common)

2) I do have 12 V at the connector to the fan clutch (pin 6 I think)

3) The resistance across the fan clutch was 9. 7 ohms. Problem is I don't know what it is supposed to be. Anyone now what the resistance is (Pin 1 to Pin 6)?

4) I was going to check the continuity of the line back to the ECM but what I thought was the C100 connector apparently is the C110 connector and I couldn't figure out the pinouts. (Maybe I'll try that in the morning)



I'm taking it in to the dealer to have them look at it on Monday, and want to be have as much figured out as possible, since I'm not in a position to swap it out at the moment.



I'm thinking at the moment that either the clutch is bad or the return line to the ECM is open.



John

2003 2500 rwd

 

[JStankus]

Checked the return to the ecm... well actually the fan clutch connector to the C110 connector. It has continuity. I did not check from C110 to the ECM, but that run is not in a place where it can flex and break.



So I have a P0480 code. What looks to be intact wiring. I guess its a bad fan clutch. What condition set the P0480 code?



John

 

[BGlidewell]

P0480: Cooling Fan Control Corcuit and P0483: Fan Speed

 

[JStankus]

I was wondering more what the actual conditions for the P0480 code to be set. Is it a particular voltage range seen at the ecm? Just trying to diagnose this. Cooling fan control circuit is a bit vague.



Thanks



John

 

[BGlidewell]

could be a fuse/fuseable link?

 

[JStankus]

Probably not a fusible link since there was power to the fan connector. I would assume the fusible link would be on the supply side of the circuit.



John

 

[JStankus]

Fixed

Ended up being a bad clutch itself.

No abrasions, or opens, shorts in the wiring leading up to the the fan clutch connector.



Had the dealer swap out fan clutch due to my time constraints.



AC now nice and cold, even stopped in traffic

I guess I have been running with a bad clutch for at least 2 years (maybe more). Wasn't bad except in stop and go in the middle of summer.



John

 

[AH64ID]

The clutch is a electronic viscous clutch and the ECM monitors the rpms vs the demand rpms, if its too low you get the P0483, but no CEL.

 

[JStankus]

That was the confusing part. I got P0480 fan clutch circuit problem, but not P0483 fan speed too low. That's why I spent a bit of time on the wiring. I wonder what the window is for setting the P0483 code? I definitely was not getting enough airflow for the AC to work when stuck in traffic, but not low enough to set the low fan speed code. AC worked decent as long as I was moving. It would be nice if the failed state was full on for the fan.



John