Question about wiring cooling fans in a car

[Beau]

Hello everyone, I'm new to the site and was hoping to get some help! I originally posted this question on a Toyota Celica car forum but I am not getting any responses, most likely because it is more to do with electronics in general and not the actual car.


I have a 2000 Toyota Celica GT. I am attempting to get my radiator cooling fans working, using a work-around.

I am an extreme novice in regards to wiring and was hoping an idea like this might work, but I do not know for sure, please let me know if you have any suggestions on how to improve what I am trying to do.

This is the link to where you can view the image:
https://www.dropbox.com/s/rnwlomfhmvht4ug/3.png


If the picture is hard to understand:
I am wanting to wire both of my single cooling fans together, into the interior of my car so I can use a switch to choose whether or not I want the fans on. The switch will then be connected to an inline fuse, which will be connected to the battery of the car (or some place else...any suggestions?).

One major concern I am having is this...
The fans are stock fans, which I have no idea how many amps they are each, but I am going to just assume for now that they are both 7.5 amps.
The current switch I have is 1.5 amps.
The inline fuse I have is 30amps.
The first problem I feel as though I would encounter is that the fans would be pulling the power they need through the 1.5 amp switch. If the fans are drawing at least 15amps total, wouldn't that fry the switch since it can only handle 1.5 amps? If this is true, do I just need to locate a switch that can handle 15+ amps?
Also, should I use a 2, 3, or 4 pin switch/button? A link to one I should get would be optimal if possible please!

Please let me know any information or links you could provide me to help me in fixing my current problem. Thank you very much!

 

[shortbus=]

This is something better handled by a relay at the fans and a control switch to operate the relay. A Google search on automotive fan relay will get you all you need to do it. Could I ask why your going to bypass the temperature controlled circuit in the car? Doesn't seem like a good idea to me, but I'm just an old mechanic/hot rodder at heart.

 

[Beau]

Thank you very much for your response. I am at work right now but will definitely take a look into what you suggested The reason I am trying to use a workaround is because it seems as though the wires that would be located directly below the fuses for my cooling fans are shorting for some reason. The two fans are not receiving power from the wires that plug into them, and neither is the Temperature Sensor (although all the fuses are good and I've tried replacing them). Originally, a few weeks ago I noticed my cooling fans were not on because my car overheated when using the A/C. Two fuses were blown, so I purchased two more, put them in, and both of them blew instantly. I waited a week before messing with it again and just avoided using the A/C for the time being. I purchased two more fuses (because I am stupid) and put them in, but they did not blow, but the fans didn't turn on. I know the fans work though, because I wired them to the battery at one point to see if they would turn on. I then purchased a new Temperature Sensor and installed it, but it did not change the situation at all (I bought the temp sensor before I knew that the wires weren't even providing power to it).

I also know that the relays are working.

I attempted to remove the fuse box in my car (the one under the hood) to try and locate the problem but realized that it would be extremely difficult to do, since there are so many wires below the fuse box holding it down. I wish there was another way to fix my problem but I do not know of any.

 

[KeepItSimpleStupid]

The car probably uses a relay for the fan. Some issues to look for are: Corroded connectors like the firewall and any plug/socket. Bad grounds. Electrical connectiosn to the frame that are not tight. So, instead of liking for a short, look for a loose connection.

One trick that's used to locate a short is to replace the fuse with a 12 V low current lamp (draws an amp or so). If the fan is supposed to be on AND the there is a wiring short, then the bulb will light, 0.5-1A is only 12 W and that's not enough to do damage. So, if the bulb lights start wiggling wires. A reminder, that turning the AC on usually turns the fan on independent of temperature.

Contact wear at the fan relay would be something that I would suspect because of the age of the car. What you want to do is measure the voltage across the closed contact when the fan is supposed to be on, You did mention an instant blow, so the replacing the fuse with a bulb should help you locate the problem.

Worn brushes is a common cause of fuse failure, so is hitting things, In one of my Toyotas that I owned, the inside blower was friction mounted. When the temperature was cold, the blower would move downward and the blower fan would hit, This would cause more current and an eventual failure of the brushes. I had to find a way to prevent the root cause and the Toyota fix wasn't available anymore. I didn;t replace the motor, but I did make brushes from generic brushed from a vacuum cleaner repair store. I did have to shim the brush holder with brass.

 

[alec_t]

You really need to sort out the shorting problem that blows fuses, before you start on alternative fan wiring. Otherwise you could end up with a car on fire .

 

[fezder]

This is something better handled by a relay at the fans and a control switch to operate the relay. A Google search on automotive fan relay will get you all you need to do it. Could I ask why your going to bypass the temperature controlled circuit in the car? Doesn't seem like a good idea to me, but I'm just an old mechanic/hot rodder at heart.

i had to do similar thing to my own car recently, just hard switch wired from passengers side under hood. The problem was hard to find, as it was bad contact in relay's contacs at control/temperature panel.
NOW it's fixed thought, no more jury-riggings
i hate car as environment in electric installations, all vibration, moisture, high currents and stuff make pain-in-the-ass faults...

 

[stevewaclo]

+1 on Alec_t's comment about identifying the short before you start getting creative!

Also, I'd be concerned that another driver, duly warned to watch the temp gauge and alerted to the location of the fan control, might lose concentration and allow your car to overheat, with the customary disastrous results.

Ask me how I know .

Passive control is better!

Best wishes.