Dodge Caravan 98 Cooling fan is not working

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  #1  
Old 12-05-03, 06:17 PM
Day Nam
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1998 Dodge Caravan (2.4L) Cooling fan is not working

Can anyone help diagnose what could be wrong with 1998 Dodge Caravan cooling fan?
Symtoms: cooling fans is not working at all. A friend of mine advised me to turn on the A/C. The cooling fan is not working even with the A/C compressor on. Another friend advised me to check the thermostat. The thermostat seemed to be OK. Another person asked me to check the fuse. The fuse was checked to be OK. The last thing I was advised to check is the relay. However, I could not locate the fan relay. Is there anyone who may know what could be the problem? Does anyone know the location of the relay? Thanks.
 

Last edited by Day Nam; 12-09-03 at 07:09 PM.
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  #2  
Old 12-05-03, 08:23 PM
mike from nj
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why would you want to fix something that would be free at a dealer?

yes, that terrible, expensive, (college trained), no good, (factory trained), good for nothing, (works on these everyday), always too busy for me, (seen this problem 100 times) dodge dealer does work for free sometimes, especially when it's a RECALL.

first, it would help us all, (you included) if we knew which engine you had. it does make a difference.

second, call a dealer tomorrow with your vin number and see hom many recalls you haven't had done, like #771--radiator fan relay replacement. sounds good, doesn't it?


if you have a 3.3/3.8L (????) you will also have a fuel rail recall, don't let that one go for too long.


if you still want to see it, take out the air box, including the filter housing below it, and you will see the relay mounted to the frame rail below it. why is it there you ask? it needs to be there for a constant air flow to keep it cool, as it is a solid state relay with no moving parts.

ps. the radiator fan will not come on as soon as the a/c is turned on, the high side pressure needs to be built up to a certain pressure for the fan to come on, if the ambient air is too cold, or the a/c freon is low, the high side pressure will never build up high enough to trip the fan.



let us know what you find
 
  #3  
Old 12-06-03, 05:19 AM
Day Nam
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Mike,

Thanks for a detailed reply. Today is Saturday and have about 6 inches snow on the ground so will have to wait until Monday to see if my vehicle is covered by the recall.
BTW, my caravan has 2.4 liter engine(4 cylinder). Will keep you posted with the result...
 
  #4  
Old 12-06-03, 05:53 AM
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Can I ask, what makes you think it's broke? With the weather were having, there is a chance it may not even come on, it's just to cold.
With these newer car, the fan is so quiet you will never even know it's on while driving, and the only time you may see it actually work is when it very hot out, after you turn the car off. It may stay on until the engine cools down.
 
  #5  
Old 12-06-03, 06:07 AM
Day Nam
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YellowTang,

I found out that the fan is not working while my car was idling in the driveway for about 20 minutes. The anti-freeze started to boil over and the temp gauge indicated that the water temperature was high. Thanks for your reply.
 
  #6  
Old 12-09-03, 06:51 PM
Day Nam
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How do you check for a bad relay?

Mike,
Per your suggestion, I called the Dodge dealer about the recall 771. However, I was told that there is no outstanding recall on my vehicle. My next step was to locate and diagnose the relay. I have located and removed the relay but I cannot seem to tell if the relay is good or bad. It has 4 wires (black, light green, green, and white). Any suggestion as to how to check for a bad relay? Thanks in advance. How much would I be expected pay for this relay?
 

Last edited by Day Nam; 12-09-03 at 07:13 PM.
  #7  
Old 12-09-03, 08:36 PM
mike from nj
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i guess the car is built outside the affected dates of concern. that doesn't mean it can't fail though, i've replaced a few that weren't part of the recall. it was a good try though

you might be mistaking the white wire for a gray

the gray should be 12volts positive from the fuse
the dark green goes right to the fan
the black is a ground for the relay
the light green(with a dark blue tracer) is the computer command of the relay (provides a pulsed ground)


i would jumper the gray with the DARK green wire with a paper clip, the fan should work.

the new relay has to be bolted up to work correctly, as it is also case grounded. it's mount to the frame is very important, it must be tight and use the new screws supplied, as the vehicle's frame is also the 'heat sink' it keeps the relay cool.

all the relay is, is a switching transistor, if you're into electronics at all, it wouldn't be too hard to make one yourself. i don't know prices, parts dept. is different than me.


(did you try it)
 
  #8  
Old 12-10-03, 04:08 AM
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The relay is around $70.00 It has been updated at Mike eluded to and comes with new screws. My price may be off due to that event. I dont think we paid that much for the few I have done lately. Another thing that can be causing this problem is the coolant temp sensor. Most of these vans that I have worked on do no command the fans to come on until around 201+ degrees. If the temp sensor is a little lazy then this can cause the fan to not come on before the coolant reaches boiling temps.
Hope this helps ya,
Billy

I had to find this out with the scan tool.... Sitting in the van watching the temp on Datastream.
 
  #9  
Old 12-10-03, 05:45 AM
Day Nam
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What about the computer output?

Mike and Billy,

I plan on doing what Mike suggested. I am pretty confident that the fan will turn on when I short the two wires (grey and green). To be 100% sure that the relay is bad(before I invest $70), I would like to know if the computer is putting out the pulsing signal as Mike eluded. What is the best way to check that? I only have a Volt/Ohm meter. What is the probability that the computer end is not working? Thanks for any input.
 
  #10  
Old 12-10-03, 11:29 PM
mike from nj
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anything is possible, although i'd have to say computers (processors) have gotten pretty reliable.

this is actually one thing i've never tried. at first, i thought to say to put a testlight to that circuit, and see if the computer grounds the light. but as i think about it, maybe there's not enough resistance in that bulb(like 1.5ohms)and you might cause a problem in the computer. there are 10M ohm (10,000,000) testlights, perhaps just for this purpose, but i haven't bought one yet. you probably can't ohm the wire through the computer to ground, as the circuit needs to be dead for an ohmmeter to work properly. maybe hook up one lead from your voltmeter to battery positive, and on the other probe, read that wire and watch for a ground to appear. what you really need is one of those high dollar, expensive handheld oscilloscopes to watch the computer provide the pulsed ground. after you buy one, then i will too (not).

don't even think of using your volt/ohmmeter unless is clearly states on the case--"10 mega ohms resistance"--- an old style analog 'sweep' (needle type) meter isn't one of these. if it doesn't say it somewhere, don't use it. you need all that resistance built in to the meter to keep from hurting sensitive circuits, just like this one.


note: unplugging the coolant temp sensor will command the fans on to high (100%), this is if you don't want to wait around until the engine reaches 220 degrees, to trigger the fan.

this will also make the check engine light come on, and store a code. no harm done, simply replugging it back in and 3 complete trips(cold engine-->warm engine, restart it cold and drive again) once the computer sees it working for 3 trips, it should shut the light off and erase the code after 50 start-ups after that.

let us know what you end up doing
 
  #11  
Old 12-11-03, 10:38 PM
mike from nj
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would you believe the guy working next to me replaced a fan relay on this type van today?

it was $65 list and had no screws in the box, it's part# ended in 'AF'

one last thing, the computer might be sending 'battery voltage' on that control wire, to enable the relay, the book doesn't specify either way which it is. i remember on other makes of cars, to energize a solid state relay like this, it does send down voltage.
 
  #12  
Old 12-14-03, 06:24 AM
Day Nam
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Smile Replacing the Relay fixed the fan problem

Per Mike's Suggestion, I shorted the two wires (grey and green). The fan immediatedly turned on. However, the shorting wire (twist wire from toy packages) turned it red hot. Of course, I removed the wired immediatedly. NO damage was done. I assume that the shorting wire was too thin (too much resistance) for supplying the current to the fan motors. This test gave me enough assurance to invest in the new relay.

At the local Dodge parts dept, I paid $67.46 (including tax) for the relay(P/N 4707286AF). This also did not include the screw so I ended up using the old screws. Anyway, just after replacing the relay, I expected the fan to come on but it didn't.(with the A/C on). So, I was a little disappointed. So, I pulled out the temperature sensor. Then the fan started to run. Next thing I noticed is that the "check engine light" come on, which concerned me. (Note that I did not read Mike's last 2 messages while I was doing this work).

So, the bottom line is that the fan is now working.
Thanks a million to Mike.

Question: why doesn't the A/C kick off the radiator fan? I expected it to work similar to the household A/C. The outside fan always comes on as soon as the A/C is turned on.

PS. We had 6 " of snow when I first posted the message. We have another 3" of snow and more is coming as I write this post.
 
  #13  
Old 12-14-03, 07:37 AM
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The A/C side of the fan controls are tied to a pressure switch in the high pressure line. It won't come on until the pressure reaches a predetermined point.
 
  #14  
Old 07-01-09, 02:24 PM
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cooling fans relay?

I have an 98 Caravan and my cooling fans dont go off, can someone tell me if my relay is bad would it cause the fans to run continues? i would like to fix this myself. ty for your input.
 
  #15  
Old 07-01-09, 02:56 PM
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4 or 6 cylinder?

Is your check engine light on????
Do they shut off when you shut down the ignition?

Bad Relay, open coolant temp sensor, bad ignition switch and a host of other issues are alll possibilities....

This post is 6 years old, you may want to start your own , instead of "Tailing " on this one....
 
  #16  
Old 07-01-09, 04:15 PM
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Is the radiator fan itself seized? If that is the case you will need to replace the unit (probably $50 at a used parts yard). Possible DIY but it may be a very tight fit getting it in and out between the rad. and the engine.
 
  #17  
Old 07-01-09, 10:07 PM
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Thank you very much for help, yes check engine light is on do to me removeing 40amp fuse to kill the fans.............it is a six cyl.......and no the fans do NOT go off with ignition
 
  #18  
Old 07-02-09, 01:56 PM
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information

this information was useful.
 
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