Radiator Fans do not come on

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  #1  
Old 10-02-05, 02:44 PM
nortme
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Unhappy Radiator Fans do not come on

I have a 97 Dodge Grand Caravan that is overheating. The radiator fans do not come on, it is not the fuse. What is the most likely cause? How can I troubleshoot other possible causes?
 
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  #2  
Old 10-02-05, 05:21 PM
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Check under the airbox for the radiator fan relay. Very problematic. There was also a recall on some of them. Check with a local dealer to see if it applies to your vehicle. Make sure the connector isn't rotted. Make sure to replace it with an oem part.
 
  #3  
Old 10-02-05, 06:58 PM
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There is also a temperature sending unit that could either have failed or have a corroded connection. If your vehicle has air conditioning, try turning it on to see if the fan comes on. If not, look at the relay that the previous poster mentioned. During this time, don't let the engine idle too long with the A/C on. When there's no airflow over the condenser, pressure builds up greatly and the A/C pump may start venting coolant.
 
  #4  
Old 10-03-05, 04:31 PM
bigmuffler22
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[what ever you do dont drive it it will blow your head gasket and it will cost more
 
  #5  
Old 10-04-05, 01:53 AM
lanceisme
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troubleshoot

i would say the best way would be to run a hot wire from battery and see if it comes on if it dont fan motor shot if it do than check relay unless it has some kind of anti theft code bull crap than buy a manual and go from there
 
  #6  
Old 10-04-05, 03:06 AM
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A 99 van has the ground for that system under the battery box. Also there is a relay mounted on the frame rail on the drivers side. It is a small box about 2 inchs square. If it is the same as a 99 then those are the two things the cooling fan and air cond run off of.
 
  #7  
Old 10-05-05, 06:10 AM
nortme
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Found the relay, OEM replacement is $82. I hate to spend that when that is not the problem. No clear wiring issues seen to and from the fans and relay. If I remove the relay I should be able to do a continuity check to ground, correct? Bad relay, poor ground, or bad PCM (in that order) are the only things I can think of being a problem. No check engine lights on so I am guessing PCM is okay.

Also, to earlier response, no radiator fan action when the A/C is turned on.

Had someone suggest getting the relay from a junk yard to test and prove that is the problem (lower cost of testing it out). Is this a reasonable suggestion?
 
  #8  
Old 10-05-05, 06:29 AM
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both fans ground with the relay, last junk yard relay I got was 10 bucks. Can you find a used one?
 
  #9  
Old 10-09-05, 11:23 AM
nortme
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Thumbs down Still no luck

replaced the relay, fans still don't come on.

Did a hot jump test of the fans they do come on. Weird thing I did a continuity check of the wiring at the closest connection of the relay to the connection at the fans. I got continuity from one connector pin to both connections on the other end of the wire (as if the wires were shorted) but again the fan ran fine connecting through that connector.

Checked ground wires under the battery, they looked good. What I can't or don't know how to check is the wiring to and from the relay to the PCM.

What on earth is going on? Oh yea, I previously replaced the sensor so I can't believe that is the issue.
 
  #10  
Old 10-09-05, 11:50 AM
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Did you get a new OEM or a junk yard part?
 
  #11  
Old 10-10-05, 09:02 AM
nortme
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The relay was OEM, it was a pain to get electronics from junkyards. Anyways, a customer service guy at the dealer mentioned that the PCM may not be sending a ground. Don't know how to diagnos or to fix.
 
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