Radiator fans drained my battery!
 

Yea the fans ran for a good 20 minutes after the car was shut off and it drained the battery. batteries good only a year old tested it myself so wtf :(

You sure your battery was getting a charge when it was on? it doesnt take much current to run a car but it takes a lot to start it.... Just a guess, maybe battery only had 7 volts when you turned it off.

i dont think 7 volts would crank it. i checked the amperage outputo f the alternator and its fine, and battery shows ~14.7 volts while running and 12.5 volts when sitting (before now, havnt checked it cause its obviously low)

Have you checked the amps of the radiator fan drain? Maybe you have a leach drain...

my multimeter wont read amps..a budyd of mine blew the fuse for it checking his damn alternator output in amps...

where would i check for leakage? and under what specs?

When everything including the fan is off take your neg terminal off the battery, hook up one lead to the neg clamp and the other to the neg terminal, without your key in the ignition it will tell you if you have a system drain. expect up to max of 5 volts for things like your clock and radio but if you have battery voltage traveling through you most likely have a system drain

so put the multimeter between the neg cable and the neg battery terminal? gotcha makes sense. thanks :)

Running the fans for 20 minutes is really a long time. No wonder your battery was low.

yea that was my original thought, why would they run for so damn long. the fans had just kicked on before i turned the car off. i rewired the plug for the sensor on the waterneck for the fan relay, perhaps something went goofy? if it didn though youd think it would constantly make em run but they acted normal when it was running.

Shouldn't that read, "battery drained by radiator fans"?

You have to ask yourself WHY they fans ran for 20 minutes. That is way too long.

It was supposed to read "radiator fans drain MY battery" lol typo

yea im trying to figure out why they ran for that long to.

Mine did that same thing a few times when I had the fan mod hooked up. After the 2nd or 3rd time dealing with a dead battery, I disconnected the fan mod.

Good luck with getting your problem fixed.

If you have grounded your wire permanently on the fan mod wire, that is the cause of your problem.

i didnt do the fan mod.

Which sensor?

the wire broke from the fan thermosensor sensor plug on the waterneck, the second one down on the back of it. i took the plug off the sensor, soldered a new wire in place and then to the original wire it broke from, and plugged it back in. I guess i should check to make sure that the wire is seeing + voltage. im not sure how the sensor is set up to control the fans, but maybe there isn't + voltage at the wire and when the fans kick on it doesn't read a temp drop to signal it to shut off? but wouldnt the same sensor be responsible for turning them on?

The fans use a lot of power; it's no surprise that they drained your battery. That's what happens when you run fans without the alternator recharging the battery.


It's possible that your battery was a little low before you shut the car off, but I wouldn't be too surprised if 20-30 minutes of fans at medium speed killed a battery with a full charge.


-s-

Check this thread for info on how the cooling fans are triggered:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/2-trigger-cooling-fans-462760/

-s-

thanks

dude with studyign for exams that was too much new info for my mind to take in tonight lol. good info though. so pretty much all 4 relays are active for the car to run at medium fan speed when it's off...eh

hey, who fixed the type in the thread title? thanks to whoever did :)

I'd venture to guess it's the wiring you monkeyed with "clue" did it do it before you changed the wiring ?

I'm of the opinion that you either messed with some wires other than just the coolant thermoswitch, or your wire looms leading from the fan relays have an open ground fault somewhere.

well the fans came on fine before i even fixed the plug for the fan thermoswitch. i just fixed it since i figured it should be done. i guess ill unplug it and let them come on and see if they stay on for that long again