aux fan failure confirmation

[DTM_Theory]

Just recently completed my cooling system overhaul, and I decided to test temps while the A/C being on. I noticed the aux fan wasn't turning on at all. Even after a roughly 15 minute drive with temps fluctuating between 92-96c. I suspect this is the reason why it snook up to 98c for a moment while at a stop light, without the a/c on. Ambients temps were about 57-61F during the drive.

after some searching here i've tried a few things;

- turned on a/c with the car on; aux fan didn't turn on

- tried unplugging the a/c pressure switch, a/c on, with car running; aux fan didn't turn on.

i'm on the verge of replacing the aux fan myself but i'd to know if there's anything else i can try before making the purchase. Could this be an issue with the wiring harness possibly?

thanks

[andrewwynn]

The fan should turn about 1/8 of a turn every time you turn on the key.

The main test people use is what you did pulling the pressure switch on the AC will make the fan spin full speed.

The proper test is to use a bidirectional scanner like the Foxhall 510 or Foxwell 710, and then you can just command the fan on at different speeds


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[DTM_Theory]

Just to make sure. This is the AC pressure switch right?

image

I tried recording a clip of the blades with my phone, turn the key twice, no aux fan response at all.

[andrewwynn]

Yup


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[X5chemist]

Welcome to the site. The aux fan normally turns on shortly after the A/C is turned on. Buy a brushless replacement. TOPAZ makes a nice one. I have one running for 2 years. It takes almost 32 seconds after cutting power for it to stop turning. Brushless fans are very efficient.

[andrewwynn]

I think you’re supposed to replace it from the below, but I was able to replace mine from above.

[DTM_Theory]

Originally Posted by andrewwynn

I think you’re supposed to replace it from the below, but I was able to replace mine from above.

Was this with or without unbolting the bumper frame?

[DTM_Theory]

Originally Posted by X5chemist

Welcome to the site. The aux fan normally turns on shortly after the A/C is turned on. Buy a brushless replacement. TOPAZ makes a nice one. I have one running for 2 years. It takes almost 32 seconds after cutting power for it to stop turning. Brushless fans are very efficient.

Thank you. I think i'll go with that. It's cheaper than the Tyc one that was suggested here too.

[workingonit]

Originally Posted by DTM_Theory

Thank you. I think i'll go with that. It's cheaper than the Tyc one that was suggested here too.

When I replaced my AUX fan last August, I went with X5chemist's recommendation of the TYC fan. At that time, it cost $190 at Amazon (where I bought it from, due to Prime free shipping and getting a discount from them), and see that now Amazon lists it for just $170 (a good deal in my book). It runs so quietly/smoothly, that you can't feel or hear it from inside the X.

The TOPAZ replacement fan , also from Amazon, is half the price, at $95, and may or not be of comparable quality, but given the time and effort spent in installing the AUX fan (especially for an old guy, in direct sun, in 100F+ temperatures), once and done was my choice prompting buying a more expensive fan.
above & below-bumper pieces removed for the install

I think I'd rather go with a recommended/quality part than try another without a recommendation. Perhaps TOPAZ is just as good, but who knows for sure?

I've never had problems with Taiwan-sourced paerts, but have had several with mainland Chinese-made parts, previously. It all depends on the QC given by the "brand" owner, since many Chinesium parts are first-rate, with ones made at the same facility that are seconds, but acceptable to a differnt "brand" owner. I've got some cheap tools and (many) electrical parts from China, but I try to have back-ups for all, just in case. But, as I stated, I'll not be happy to do another AUX fan install, anytime soon.

[DTM_Theory]

thanks for the feedback. i'm always open to suggestions. I'd rather buy once, cry once when it comes to anything involving the cooling or HVAC system. you've got a point. what would be the benefit of a brushless fan otherwise? that had swayed towards the topaz option.