fans never run
Thread Starter
Staging Lane
Joined: Jul 2008
Posts: 81
Likes: 0
fans never run what do i do about my fans never turning on. the only time i have ever heard them or seen them come on is when i turn the a/c on. during traffic jams and slow traffic or just idling somewhere my cars temp sky rockets, until i turn on the a/c and the fans kick on. any ideas?
Mine got extremely hot in the summer time at red lights at stuff. When I got my car tuned I had them tune my fans to turn on earlier. Ever since it runs cool as a breeze even sitting idle for a long time
If they arent turning on at all I doubt it is in the tune, they are supposed to turn on at around 220 i belive. You can get a mailorder tune or an email tune since you are in hawaii. If there is a shop around you they may be able to do it.
Worst come to worst a Hypertech handheld lets you change your fan settings.
Personally I'd wire up a cheap switch and see if that fixes it.
In my 94 I ran a wire under my low fan relay and grounded it between my brakelines. It was a little ghetto, but i ran it like that for a year and the fans would run when i had the ignition switch on.
Worst come to worst a Hypertech handheld lets you change your fan settings.
Personally I'd wire up a cheap switch and see if that fixes it.
In my 94 I ran a wire under my low fan relay and grounded it between my brakelines. It was a little ghetto, but i ran it like that for a year and the fans would run when i had the ignition switch on.
Trending Topics
Im not sure how to wire the switch, I believe there may be a right up on shoeboxes website though. Like i said I just grounded out one of my relays.
Doing this will fix the problem but if you want it "fixed" you may have a problem elsewhere, the fans should be coming on by themselves.
Try testing your relays and see if you can make the fans come on like they are supposed to. I switched mine around with my a/c relay because I knew it was good.
Doing this will fix the problem but if you want it "fixed" you may have a problem elsewhere, the fans should be coming on by themselves.
Try testing your relays and see if you can make the fans come on like they are supposed to. I switched mine around with my a/c relay because I knew it was good.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo All you are doing when your switch it around is finding out if the relay is bad or not. If it is bad, and the fans come on at 220 degrees or whenever they are supposed to come on stock, then you can go buy a new relay to replace it.
Changing relays wont make the fans run all the time though, just when they are set to run from the factory.
Changing relays wont make the fans run all the time though, just when they are set to run from the factory.
Yes, the lid on the relay box has a diagram that shows what each relay is. They just pull out and push in, just be kind of careful with them.
I suggest the A/C relay because you know it is good and you dont need it to run the car. Try switching it with the low speed fan relay and see if they will come on then.
I suggest the A/C relay because you know it is good and you dont need it to run the car. Try switching it with the low speed fan relay and see if they will come on then.
On some year models both fans run at the same time at a low speed and then a high speed if the engine gets too hot. Im not sure on the temps that they are supposed to run though. On other year models one fan will run and then the other will kick on when it gets too hot.
EDIT: I just had a better idea, take your relays out of the fan slots and put them in the A/c slot and see if the A/C kicks on, that will be a lot easier and quicker than trying to wait for the fans to kick on with the a/c relay in.
EDIT: I just had a better idea, take your relays out of the fan slots and put them in the A/c slot and see if the A/C kicks on, that will be a lot easier and quicker than trying to wait for the fans to kick on with the a/c relay in.
10 Second Club
Joined: Oct 2007
Posts: 2,630
Likes: 28
more than likely the relays went bad... i had both of mine go bad at the same time in my ta and i had the same problems as you described... might want to just look into replacing them
i didn't know the fans still turn on with the a/c if the relays are bad?
here's some wiring for ya, irocchenault.
http://shbox.com/1/fan_schematic_1995.jpg
http://shbox.com/1/schematics_wiring.html
On The Tree
Joined: Nov 2007
Posts: 130
Likes: 0
The computer (PCM) runs the fans from the temp signal off the sensor on the WP. Depending on car early '94's and earlier have two relays and run 1 or 2 fans. Later '94's and up have three relays and run both fans on low or both on high speed. Low or fan 1 signal is at 225* and high or fan 2 signal is at 235 (pretty high on the gauge). Also when the PCM sees A/C refrigerant pressure from the A/C sensor switch it sends the low speed signal to the fan relays, just the same as it does when it sees 225*. Therefore if the A/C runs the fans on low (3 relay system), or fan 1 (on 2 relay system) the relays are working. The fan switch modification dummies up the low/hi picks from the PCM, but the relays still have to work. Cooler T-stat won't help unless you reprogram the fan turn-on, have you waited it out to see if they really come on at 225-235* maybe your temp sender for the gauges (in the head) is bad and reading high. Is this thing boiling over or just looking hot ?
Last edited by bobdec; Jan 7, 2009 at 10:03 AM. Reason: changed temp sensor in block to temp sensor in head