Hi, If anybody can help me out here with advice or where to look next, I would be really gratefull !
Ram 1500, 2004, 5.7 Hemi, AWD, Auto.

EML Light came on, Code P0480, Fan 1 Control Circuit. So i proceeded as follows.
1. Checked the relevant 10amp, and 30 amp fuses in the fuse box. all ok, replaced with new anyway. Still the same !
2. Swapped out the relays with new ones. Still the same.
3. Removed the fuse box and thoroughly checked all the multi plugs that fit in the bottom. All were corrosion free, nice and dry, no apparent signs of chaffed, worn or damaged wires. Still the same.
4. Checked the plug going to the Condenser Fan Motor. No power going to the fan !!
5. Checked the relay socket in the fuse box. See attached pic. 2 pins (coloured red) both live constantly. I ran a temp jump wire from a Positive supply to the pin marked in white. Fan did run, but was very noisy, smelt of burning. I take it the pin marked in blue is the Earth from the ECM ??
6. Removed the Condensor and fitted a New Fan Motor. Also removed the AIR-CON Pump and replaced the Coolant Temp Sensor, just too be sure. Re-fitted everything, re-gassed up the system. Reconnected the battery, all seemed good. No EML warning light. Went for a run and parked up.
Next morning, EML light back on !!! Had a quick check underneath, and with the Aircon switched on, again, no power to the plug at the Condensor Fan ??
Any ideas where to check next ?? Pics attached. Thanks in advance, Alan..........

 

Is the PCM actually trying to control the condenser fan? (grounding pin 86 on the relay?)

 

Electrics is not my speciality mate. Is there a safe way to ground out pin 86 ? and i will certainly check that out. Thank you. Should add here, I am in Scotland, in the UK and its very rare to need Aircon ! Always freezing here ! 😀 More interested in getting the warning lamp out !

 

Pin 86 should go to the PCM, and it should ground it when it thinks the fan should be on. Do whatever to make the PCM think the fan should be running, then test pin 86 and see if it goes to ground. (resistance check, or even continuity check will work.)

 

Thank you. Will get on that tomorrow !!!

Cheers, Alan.............

 

Good Luck.

 

Not saying this is your problem, but be aware the IPM circuit board traces tends to corrode, you can crack the case open pretty easily and check the board for open traces. If that is what is wrong, I've had success soldering in a jumper to complete the circuit.

 

I live in fear of Spiking the PCM ??? When you say, Pin 86, are you referring too the number on the Relay ? Would it be ok to run a jumper wire to the relay socket that Pin 86 fits in to, and ground the jumper cable ?? Sorry if this seems obvious, but just want to make sure ? Weather was in the Minus today ! Way too cold to be guessing ! Alan........

 

Yep, that will trip the relay at least. And yeah, working outside in the stupid cold temps ain't my idea of a good time either.

 

OK. So i ran a jumper wire from Pin 86 to Earth. With the ignition on, and the Air-Con switched off, the fan runs constantly. Same with the Air-Con switched on ? What i also noticed was, the clutch engages, and disengages at random, regardless of whether the truck has warmed up, or after a cold start, even with the Aircon switched off ? This is confusing ?