P0481 and Radiator fan relay fuse keep blowing.

Tiny
BCMULLEN95
  • MEMBER
  • 2006 CHRYSLER PT CRUISER
  • 48,236 MILES
I have tested to see if would be part of the thermostate circuit and disconected the fan, fuse did not blow. However when I reconnected the fan and started the car drove it around the block the fuse still did not blow.
Could this be a possible high speed relay issue that is not working correctly. I have read that it could be the fan also, but the fuse does not seem to blow at low speeds.
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Tuesday, April 10th, 2012 AT 10:50 PM

7 Replies

Tiny
BCMULLEN95
  • MEMBER
Both relays have been replaced.
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Tuesday, April 10th, 2012 AT 11:02 PM
Tiny
CARADIODOC
  • EXPERT
Spin the fan by hand to see if it's free or tight. A tight motor will draw excessive current leading to the blown fuse.
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Tuesday, April 10th, 2012 AT 11:02 PM
Tiny
BCMULLEN95
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It spins freely. I did find out that the relay that was replaced are the two by the fan. I will be checking the relay behind the bumper tomorrow. Is there anything else that will ne to be looked at?
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Wednesday, April 11th, 2012 AT 4:01 AM
Tiny
CARADIODOC
  • EXPERT
I can't get into the Chrysler web site right now, but you might look for a 4-terminal electronic relay connected to the fan motor. They went to that design in the mid '90s to allow for variable speeds to address the people who were whining that they could "hear" the fan turn on when they were stopped in traffic. Being an electronic module, they cause a lot more trouble than a standard relay.

Also consider that the engine rocks when you accelerate and tugs on wiring harnesses. I helped a friend with a Caravan that blew the radiator fan fuse intermittently. At about the fourth time in the shop I also noticed the backup lights weren't working, but they were okay after he replaced the fuse link yet again for the fan. The next time he fixed it and started to back out of the shop, I saw the backup lights go off. Checking right then proved the fuse link was blown again. Turned out to be the wire harness running under the battery tray had been sliding back and forth for years and the wire going to the radiator fan was rubbed through and bare. The backup lights were on the same circuit. Chrysler does that a lot. You might never know your backup lights aren't working, and that could be a safety hazard, but you will notice when the engine runs hot.

Another approach is to unplug the fan, then drive only at higher speeds so the fan isn't needed. Plug in a pair of spade terminals in place of the blown fuse, then run a pair of wires from them to a 12 volt light bulb. You might also want to bypass the relay so the circuit is powered up all the time. Hang the light bulb where you can see it while you're driving. Since the circuit is turned on by bypassing the relay, if the short occurs, the bulb will be full brightness and will limit current to a safe value. If the bulb turns on with the fan unplugged, there's proof the short is caused by something other than the fan motor.

The fan motor could be acting up intermittently too. It's not as common for them to short but it is possible. Usually the brushes wear and make intermittent contact.
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Wednesday, April 11th, 2012 AT 4:47 AM
Tiny
BCMULLEN95
  • MEMBER
For what ever reason I cannot see to find where the issue is. I drove the car at high speeds and at low speeds, but the fuse did not blow. Is there a way I can get a copy of the wiring schematic for this car that deals with the fan and the relays as well as the ground schematic so I can check all the ground to ensure a ground is not coming loose.
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Wednesday, April 11th, 2012 AT 9:24 PM
Tiny
CARADIODOC
  • EXPERT
A loose ground won't cause a fuse to blow because that will reduce or stop current flow. Fuses blow in response to too much current.

Did you have the fan disconnected while you were driving the car? If so, the relay should have turned on shortly after slowing down or standing still with the engine still running. All you can say for sure is if the fuse blows while the fan is unplugged, the fan motor is not the cause. Intermittent problems like this are always the most frustrating to find, and a lot of people get angry with their mechanic when he doesn't "just fix it".

If you wait long enough with the engine running, the fan will turn on while you're standing there. Listen to how it sounds. It should be running fast enough and not be making any squealing sounds. If it runs normally, flex the wire harnesses to see if anything makes it stop or slow down.

The closest book I have is for an '01 Neon, and that shows just a basic, simple, reliable fan relay and motor with a 30 amp fuse. All that can be wrong there is a grounded wire or bad motor. My next suggestion is to click the link right below here for Mitchell Manuals. I have never been able to even get to he sign-in page without getting an error message so you might also go to:

http://randysrepairshop.net/index.html

then click on the AllData picture.

Either site will give you access to diagrams and repair procedures, but while you can own the manufacturers service manual forever, the online services also give you service bulletins, recall information, part numbers, and lots of other things like that. A five-year subscription for one car model costs about half of the Chrysler service manual and gives you much more information.
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Wednesday, April 11th, 2012 AT 10:03 PM
Tiny
BCMULLEN95
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The fuse was when while driving and as I let it sit at home I could here the fan speed up and slow down. I will check to see if it is any of the wires, I did not notice any wires that where in bad shape, but I will keep looking. I am suspecting the fan since it is a dual speed and there are a lot of problems with these fan modules going bad.
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Wednesday, April 11th, 2012 AT 11:31 PM

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