Electric Radiator Fan Not Working

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jerbo1978

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Just bought a 2012 Ram 1500 quad cab with a 4.7.
When AC is turned on the check engine light comes on.
Fault code is p0481 which is cooling circuit II malfunction.
Electric fan isn't coming on.
Checked all fuses and they're good.
I switched the power window relay out with the fan relay and the power windows still work so I don't think it's the relay.
Unplugged fan and ran battery wire directly and the fan comes on.
I pulled the relay from the rad support and bypassed it and the fan comes on.
I dont think its getting a signal to turn on.
Any suggestions would be welcome.
thanks
 

csuder99

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Pretty good tests so far, just continue down that path: jump the connection in the fuse box/TIPM to check if the fan comes on, use a voltmeter to check if the PCM has control of the relay. Check the control and the ground for the relay.

I'm not familiar with the 4.7 Rams so I'm wondering about the "rad support relay". It seems weird to have two relays, is that possibly a speed controller ?

Edit: So I found a 2008 FSM buried way down in my folder structure :) Apparently the 4.7 has a mechanical fan for the engine plus an electric fan that kicks on when the AC is on. The latter one is likely controlled by the external relay at the rad support. So check if the relay gets activated when the AC is turned on.
 
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jerbo1978

jerbo1978

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@csuder99,Thanks for replying,I appreciate it.
There are 2 relays,the one in the fuse box is low speed relay so it says,the one on the rad support is high speed?
The one on the rad support has 2 large wires- green with blue stripe and red with brown stripe.
Also has 2 smaller wires which I think are signal wires.
Both are brown but one has a light blue stripe and the other has orange stripe
 
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RamDiver

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@csuder99,Thanks for replying,I appreciate it.
There are 2 relays,the one in the fuse box is low speed relay so it says,the one on the rad support is high speed?
The one on the rad support has 2 large wires- green with blue stripe and red with brown stripe.
Also has 2 smaller wires which I think are signal wires.
Both are brown but one has a blue light stripe and tge other has orange stripe

Great work on this for all involved.

So, it's looking much like relay #2 on the rad is suspect, or at least the driving circuits for the same. I found this tidbit that may help a wee bit.



PO481 Dodge cooling fan #2.jpg

P0481 is a diagnostic trouble code (DTC) for "Cooling Fan 2 Control Circuit Malfunction". It means there is a problem with the control circuit for cooling fan 2. The PCM controls the cooling fan by grounding the cooling fan control circuit which turns ON the cooling fan relay. This code is detected when the Powertrain control module (PCM) detects that the commanded state of the driver and the actual state of the control circuit do not match. When the Powertrain control module (PCM) cannot control the cooling fan as desired, it will set code P0481.

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RamDiver

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Just bought a 2012 Ram 1500 quad cab with a 4.7.
When AC is turned on the check engine light comes on.
Fault code is p0481 which is cooling circuit II malfunction.
Electric fan isn't coming on.
Checked all fuses and they're good.
I switched the power window relay out with the fan relay and the power windows still work so I don't think it's the relay.
Unplugged fan and ran battery wire directly and the fan comes on.
I pulled the relay from the rad support and bypassed it and the fan comes on.
I dont think its getting a signal to turn on.
Any suggestions would be welcome.
thanks

Does this look like your TIPM fuse/relay layout?

2012 TIPM layout.jpg

If so, fuse #34 is identified as the fuse feeding the high-rad relay.


.
 

RamDiver

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Yes,it does

Excellent, then you can save the link and/or print it for future reference.


Could this be a problem?

You may want to fix that up before spending much more time chasing electrical gremlins. :cool:


That's the Coolant Temp sensor connector

A second set of eyes is often productive while troubleshooting weird and wonderful faults like this. There are just so many variables with today's vehicles.

.
 
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jerbo1978

jerbo1978

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I'm glad I have input from this forum..
It's a big help for sure...
I can probably order one of those connectors online..
Or maybe one of the local parts stores will have it.
Just cut-splice-solder-tape the new one on???
 
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jerbo1978

jerbo1978

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Excellent, then you can save the link and/or print it for future reference.




You may want to fix that up before spending much more time chasing electrical gremlins. :cool:




A second set of eyes is often productive while troubleshooting weird and wonderful faults like this. There are just so many variables with today's vehicles.

.
I checked that fuse M34...and it's a good fuse....darn it
 

RamDiver

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I checked that fuse M34...and it's a good fuse....darn it

Leave no stone unturned when chasing electrical demons. :cool:


I'm glad I have input from this forum...
It's a big help for sure...
I can probably order one of those connectors online...
Or maybe one of the local parts stores will have it.
Just cut-splice-solder-tape the new one on???

Could you please provide a closer picture of that connector? Try carefully moving the red cap up first but be careful that the wires don't disengage from the bottom section.

I may be wrong but, if that's the type of connector it appears to be, slide the red cap up, and the wires may just pop off the receptacles.

Clean up the wire ends (cut and restrip if necessary, pay attention to stripped wire length), re-insert them into the receptacle, and press the red cap down on top again.

Take a pic first to capture the wire positions before disassembly.

.
 
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jerbo1978

jerbo1978

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The red cap is a lock.
Slide it up then push in on the release tab.
Red cap is just a safety lock preventing the connector from coming off
 
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jerbo1978

jerbo1978

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Any ideas on what this thing is ?
Location is on the drivers side below fuse box
Screenshot_20230426-114711_Gallery.jpg
 

RamDiver

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LOL, I should have asked for the close-up first.

Could you disassemble and inspect the contacts for corrosion? Also, confirm that the inner crimp lugs are securely fastened to the wires and they're not loose.
 

RamDiver

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The one wire is exposed
Are you referring to that small bit of copper from the green wire in your first picture?

If the wire is still well attached at the crimp point, not damaged or loose in any way, I'd apply a bit of electrical tape and if you really want to go all out, find a piece of heat shrink just large enough to slide over the connector.

Changing that connection out for anything but a performance issue, may create more problems than it's worth unless you do this type of work regularly.

If you do that sort of work, great but, you might wait until we're finished unless testing tells you it's a problem.

I worked most of my life in electronics and wouldn't bother with a full replacement if it were mine unless you can identify damage or a specific performance issue.

All that said, it's your truck and your call, I'm just trying my best to get you to the easiest and most reliable solution. :cool:

.
 
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