if i got the automatic fan on/off would i have to change wiring

Discussion in 'Fox 5.0 Mustang Tech' started by sidewayzisbest, Dec 20, 2003.


  1. sidewayzisbest

    sidewayzisbest New Member

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    Well my mark 8 right now is turned out whenver you turn the key and it works i was plannin on putting the switch but would i have to change anything if i bought one of those universal kits from autozone?
  2. TIMMY2734

    TIMMY2734 Founding Member

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    Just put the switch between your switched 12v source.
  3. sidewayzisbest

    sidewayzisbest New Member

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    im talkin bout the kits that come on a certain degree and turn off since i dont have my phantom gauges like i plan and woulnd't know for sure if the stock gauge even works now
  4. sidewayzisbest

    sidewayzisbest New Member

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  5. HISSIN50

    HISSIN50 "How long does it take to get help in here? SN Certified Technician

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    sidewayz, not to get off topic, but since im giving you a bump, ill do it anyhow. does autozone sell a universal kit with an adjustable fan switch sending unit for the fan (i.e., choose what temp it kicks on and off at)???????????????

    im trying to find one for my g/f's 94 camaro. the stocker kicks on insanely high (like ~230*). i was gonna run a switch, as the kits that camaro and Lt1 sites sell are 60 bucks, which is insane.
    sorry to get off topic.

    i see no reason why you cant use on of these kits (if its like what i describe). you are basically gonna use one or two relays and the sending unit. one relay is for a/c. if you want a switch (i always do, in case you are in gridlock or the sender fails), put the switch in series with the TRIGGER wire for the relay (only will run about 50- 150 ma through the switch, not all 15 amps or whatever your fan draws). i know how to piece it together if i had an adjustable sending unit.
    if you get stuck with the wiring when you do it (or you want to put a switch on), post or pm me. im good with wiring and should be able to help. good luck.
  6. Michael Yount

    Michael Yount Advanced Member

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    That Mark VIII fan is rumored to draw as many as 46 amps (it moves something like 4600 cfm!!) -- so Hissin's right; it'll take one heckuva robust switch if you put full fan power current through it. Autozones here sell a Hayden adjustable t'stat kit for electric fans. But you need to take a close look at the capacity. My recollection is that it's rated only for about 25A. Furthermore, I tried 2 of 'em through PAW - and both units were faulty. I had to return both of them. So I'd be careful - and know for sure what Autozone's return policy is on electrical bits. If the fan pulls too many amps through it and you hook it up and toast the relay, I doubt they'll take it back.

    I'm with you on not wanting to have the fan running all the time - especially that fan. If it were me, I'd want to install a fixed temp. on/off switch somewhere in the hottest part of the coolant system (near the upper radiator hose in the radiator tank or in the t'stat housing). Let that temp. switch trigger your relay for you. I'd also have the relay charged only when the ignition switch is on - that fan draws a lot of current, and I wouldn't want it running after the car is shut off. I wouldn't use a toggle - it's just too easy to forget about it, and it doesn't take long in the right conditions to overheat an engine -- uh, especially if you don't have gauges! Even a $14 coolant gauge from WalMart is better than no gauge at all, which is pretty much what you have if you don't know if the stock one is working.
  7. sidewayzisbest

    sidewayzisbest New Member

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    yea its universal i think im going to go up there tday ( 17 bucks) and see how well if it will or wont be good for my fan i might have to end up buyin a phantom gauge if i have any xmas left over
  8. HISSIN50

    HISSIN50 "How long does it take to get help in here? SN Certified Technician

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    Michael, ah, my stock alternator would barely support that fan in and of itself. i think the gerbil would wear out. LOL (didnt remember that they sucked that much juice). good stuff.

    sidewayz, thanks for the info. i will give them a call and see about that. stock t stat opens at 180 on that camaro, but no fan til around 230. thats dumber than some of the stuff ford did. thanks. :nice:
    also, michael, do you have any suggestions? this is the type of thing im lookin at (figured id post it, in case sidewayz wanted a reference).
    http://www.martelbrothers.com/customer/product.php?productid=JET60602&cat=&page=1
    i aint even paying this much for it(1.50 worth of parts), hence my interest in the kit that sidewayz is gonna use.
  9. Michael Yount

    Michael Yount Advanced Member

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    My only concern with the switch at the link is that the off temp is too close to your 180F t'stat temp. Depending on where you physically place the switch, it has the potential to have the fan running all the time because the off temp (185) is too close to the t'stat temp (180). My experience has been that you need at least a 10F temp difference between the off temp and the t'stat temp to assure that the fan will cycle when you're running around town. From a cold start to cruising on the highway it wouldn't be a problem as the fan wouldn't activate.

    I use a 170 t'stat, with my lowest temp fan cycling with a 195F on/180F off switch. The other fan comes on at 210F and goes off at 195, if it's needed. It has yet to come on.
  10. HISSIN50

    HISSIN50 "How long does it take to get help in here? SN Certified Technician

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    Michael, you are absolutely correct. i really didnt even look at it, as im not gonna pay that much for that part, hence my interest in the autozone unit (i tried to look it up last night, their site was down. i called today, the kid thought i was nuts. never heard of such a thing. sidewayz, if you know, hit me with a part number). i will go take a look after i post this (and i tried partsamerica-checker locally, no dice). im surprised with that site, as i didnt find anything that cycles at higher temps. (i also didnt find their "application chart" -which is mentioned in the caption.

    what appeals to me is adjustability. that would be nice. i would likely try to find another place to mount it, and splice it, so the oe unit is retained (actually i have to, as it is also the pcm sensor). just something i would play with if i can find a unit for cheap. im now thinking that since the sensor is also for the puter, maybe that is why it is so expensive on that site (i found another site and they want 60 bucks. ouch)? i dunno.

    sidewayz, i really apologize for jacking your thread. please pipe in with info or questions YOU have. at least your thread is being perpetuated.
  11. Michael Yount

    Michael Yount Advanced Member

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    Hissin/sidewayz - go to any of the fan companies sites and search around. Hayden, SPAL-usa, etc. Most have adjustable t'stats shown. My experience chasing this down on mine has been that they're all (the ones with the probe that gets inserted in the radiator fins) produced by the same company, even though they're marketed under 2 or 3 different names. The AutoZone near me has carried them from time to time - seems some of the guys know about them, and some don't. But the big parts places - PAW, Summit, Jeg's - I'd be surprised if they don't have them. I got mine from PAW.
  12. HISSIN50

    HISSIN50 "How long does it take to get help in here? SN Certified Technician

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    Michael, thank you. i will get off my butt and check some sites. i figured id have to go down to the parts store and show them where their parts are (wouldnt be the first time). i know you did a ton of research before deciding on your SPAL fan, so you're the one to know. thanks again. good stuff. :nice:

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