Coolant Fan Not Working

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Coolant Fan Not Working

Postby rodeo64 » Fri May 19, 2017 7:15 am

How can I test whether the large electric fan attached to the radiator is working? Is it controlled by a fuse or circuit breaker?
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Re: Coolant Fan Not Working

Postby itsmehb » Fri May 19, 2017 11:31 am

What model and year and engine size. I know on the 2000 Amigo I had, it had a single 2 speed fan. It always came on with the air conditioner, and when the a/c wasn't on it only came on when the temp sensor told the ecm the engine was getting hot. At that time the ecm would tell the fan to come on, usually by providing a ground for the fan relay. Mine was protected by a fuse. Different years and models operate differently, but I believe they all run when the a/c is on.
1990 Amigo, 2.3 5 speed (sold)
1991 Pick up (long gone)
2000 Amigo, 2.2 5 speed(sold)
1985 Trooper 1.9 4 speed (sent back to KS)
1989 Trooper RS 2.6 5 spd. Red

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Re: Coolant Fan Not Working

Postby rodeo64 » Fri May 19, 2017 12:05 pm

2002 Rodeo LS, 2WD, auto with AC, 3.2 L V6. Mine has never ran since I got the vehicle a month ago.
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Re: Coolant Fan Not Working

Postby Buster28 » Fri May 19, 2017 2:33 pm

The engine coolant fan on a 02 Rodeo 3.2L V6 is driven by the serpentine belt. The electric fan cools the Air Conditioning (AC) condenser coils. The condenser fan is controlled by the condenser fan relay which is controlled the AC triple pressure switch (Auto transmission) or AC dual pressure switch (Manual trans). The condenser fan will operate when the AC high side pressure reaches a pressure of approximately 1471 Kpa.
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Re: Coolant Fan Not Working

Postby rodeo64 » Fri May 19, 2017 3:57 pm

For my vehicle, I have checked the condenser fan relay by switching it out with the headlight relay since they are identical. The fan did not come on. Where is the AC triple pressure switch located?
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Re: Coolant Fan Not Working

Postby Buster28 » Fri May 19, 2017 5:56 pm

Triple Pressure Switch
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Re: Coolant Fan Not Working

Postby rodeo64 » Thu Jun 01, 2017 9:42 am

I disconnected the fan and connected it directly to the battery. It works fine. No noise and turns fast. Is the triple pressure switch easily replaced? What other tests could I perform? Can I wire up the fan to a manual switch that I can operate as needed?
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Re: Coolant Fan Not Working

Postby rodeo64 » Thu Jun 01, 2017 10:11 am

I have a Haynes manual and it says that if the coolant fan is good, then check:

fuse
defective condenser fan relay
faulty AC pressure switch
bad control head

Additional info: the AC is ice cold and appears to work fine. The AC clutch cycles on an off but not excessively; seems fine.

So, what fuse are they referring to? I cannot find one specific to this fan.

I switched out the fan relay with the headlight relay (appeared to be identical); and no change.

Would a faulty pressure switch only control the condenser fan and have no other effect on the operation of the AC?

What and where is the control head? Again, would the AC system work fine (as it appears to) with a bad one?

The AC pressure switch is an easy change and costs around $60. I am just trying to narrow down what may be the most likely thing to repair.

Thanks!
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Re: Coolant Fan Not Working

Postby Buster28 » Thu Jun 01, 2017 5:05 pm

The Condenser Fan is controlled by the Triple Pressure Switch. The switch that operates the Condenser Fan closes at 1471 Kpa (213.3±14.2 psi). The normal high side pressure in the system is usually less than this so the Condenser Fan does not run all the time. You will need to check the pressures to determine if there is a problem with the pressure switch.
Throw the Haynes manual in the trash can.
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