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Auxiliary e-fan cycling

jro780

jro780

NAXJA Forum User
Location
Des Moines, Iowa
Regardless of my engine temp, my auxiliary e-fan cycles on and off approximately every ten seconds when the AC compressor is running. Is this the normal cycling rate when the AC is running? Or perhaps the cooling fan relay should be replaced? Any help appreciated. Thank you.
 
It is normal ...albeit, annoying ...for the e-fan to cycle on-and-off whenever the AC is switched on, and also when the control is set to defrost.

Both my '93, and '98 XJs do this.

Setting your climate controls to Off should quiet you e-fan unless the engine temp
exceeds 213º or so.
 
On my '93, the e-fan cycles rarely, if at all, when the AC compressor is running. (not necessarily saying this is "normal".)

In any event, the e-fan is controlled differently on later models.
 
On my '99 the auxiliary fan runs continuously with the AC compressor. It ONLY cycles on and off to maintain that ~213* threshold (low speed &/or hot weather) if and only if neither the AC nor defrost are running. It used to stick on occasionally, even after shutdown (draining the battery overnight), until I replaced the relay.

I'm gonna check it, but I've been convinced mine kicks on with the defrost BECAUSE the AC compressor comes on too for the defrost. The drain on the engine certainly feels like this is true, and it's never made sense to me.
 
Dragonslayer said:
It is normal ...albeit, annoying ...for the e-fan to cycle on-and-off whenever the AC is switched on, and also when the control is set to either defrost mode.

Both my '93, and '98 XJs do this.

Setting your climate controls to Off or a heat only setting should quiet you e-fan unless the engine temp
exceeds 213º or so.
Click to expand...

X2
 
Yes, normal it is. Makes sense however, it does not... at least to me (yet).
I don't care about "quieting" the e-fan, especially if it's needed, but I'd like to eliminate the obvious power drain just from pushing heat at the inside of my windshield.

WB9YZU said:
X2
Click to expand...
 
b.jenks said:
Yes, normal it is. Makes sense however, it does not... at least to me (yet).
I don't care about "quieting" the e-fan, especially if it's needed, but I'd like to eliminate the obvious power drain just from pushing heat at the inside of my windshield.
Click to expand...

When you select the defroster settings, the AC compressor runs. The moisture in the air condenses on the evaporator, which lets the system blow dry heat at the windshield, which is what speeds up defogging. Try blowing warm humid air across cold glass in the middle of winter.
 
jro780 said:
Regardless of my engine temp, my auxiliary e-fan cycles on and off approximately every ten seconds when the AC compressor is running. Is this the normal cycling rate when the AC is running? Or perhaps the cooling fan relay should be replaced? Any help appreciated. Thank you.
Click to expand...

I believe you have low pressure in your AC system. It cycles on until it drops below a certain amount and then cycles off. Pressure equalizes and the compressor kicks back in. Repeat.
 
thezfunk said:
I believe you have low pressure in your AC system. It cycles on until it drops below a certain amount and then cycles off. Pressure equalizes and the compressor kicks back in. Repeat.
Click to expand...

This is possible. It could also just be low demand and fan on low speed, cycling the compressor.

The E-fan will cycle on and off at the same time the AC compressor cycles on and off.
 
I thought on later years the e-fan does not necessarily cycle on and off with the compressor unless there is a pressure problem with the AC system? Not sure what model year this changed.
 
Pelican said:
I thought on later years the e-fan does not necessarily cycle on and off with the compressor unless there is a pressure problem with the AC system? Not sure what model year this changed.
Click to expand...

I have never heard of a vehicle that does not cycle the E-fan on when the AC clutch engages. IT is primarily to ensure that the condenser has sufficient air flow to condenser the refrigerant, and hold the high side air pressure down. Also that condenser heat goes through the radiator next, so more air flow is needed for the radiator when the AC compressor is running.
 
Interesting.
 
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