Jump to content
Ultimate Subaru Message Board

Rad thermo switch


Recommended Posts

If it's not the thermo switch then what is it? Does the fan not have 12v going to it?

 

Basically, the fan always has 12V to it, and the thermo switch pulls it to ground, turning the fan on.

 

I actually just reverse engineered their wiring so I could rig up a proper switch for my fan.

 

My idea is to rig a relay shorting the thermo switch, and having a switch on the dash activate the relay. That way I can manually turn it on, or change it back to auto.

Link to comment
Share on other sites

correct, I think...

 

You should be able to turn the key to 'run', then check the voltage on the yellow wire that plugs into the fan. This should read 12v. If it doesn't try the other one :)

 

If neither of them are hot, then the problem is there.

 

If you want, I can scan the picture I drew showing the circuit.

Link to comment
Share on other sites

this setup will work as long as the fan circuit itself is in order. go ahead and hook this up, and if nothing works then look at the whole circuit.

 

i have this setup as well, the relay is by the ac relays, and the switch is in a coil tray on the parking brake adjust cover

Link to comment
Share on other sites

What you need:

 

30A Switch $5

20A Fuse link $3

15ft of 14g wire $3

4 butt connectors $1

 

 

1. Cut the wires leaving about three inches on the fan, then test the two wire going to the fan, find the ground. Use a connector to extend the ground wire of the fan, there sould be a good ground to frame screw nere the air filter box (if fi).

 

2. Test the wires going to the wiper blade motor. You should find that there are two types of power lines, there is one wire that will be hot after the key is on, the other power wires are controlled by wiper switch. Cut that wire (after disconnecting the battery) and use a connector to splice in the 20A fuse. Other the other end of this fuse link use another connector for a good eight to ten feet of wire.

 

3. Run the middle of this wire down into the inner car. After you struggle with that damn boot cut the wire at about three feet from the fuse. Remove a switch cover (one of the two) and rig the switch into the panel cover. It is best if you buy a switch with a jam nut that way you can just drill a hole into the panel and relpace it. The job will look a lot better if you are able use the panel.

 

4. At this point you realize that it was a great idea to run the middle section instead of running the end of the wire into the car. For the ground use one of the hood pop bracet screws. That should only take two feet of wire. Now get the three wires attached to the switch. Pull the slack from the wire still just chill'n under the hood. Use you last connector to attach that wire to the power of the fan.

 

5. Reconnect the battery. Turn the key on and check for the fan. If she works, make sure EVERY mod wire is safe and in a good spot. Good luck!!!

Link to comment
Share on other sites

What you need:

 

30A Switch $5

20A Fuse link $3

15ft of 14g wire $3

4 butt connectors $1

 

 

1. Cut the wires leaving about three inches on the fan, then test the two wire going to the fan, find the ground. Use a connector to extend the ground wire of the fan, there sould be a good ground to frame screw nere the air filter box (if fi).

 

2. Test the wires going to the wiper blade motor. You should find that there are two types of power lines, there is one wire that will be hot after the key is on, the other power wires are controlled by wiper switch. Cut that wire (after disconnecting the battery) and use a connector to splice in the 20A fuse. Other the other end of this fuse link use another connector for a good eight to ten feet of wire.

 

3. Run the middle of this wire down into the inner car. After you struggle with that damn boot cut the wire at about three feet from the fuse. Remove a switch cover (one of the two) and rig the switch into the panel cover. It is best if you buy a switch with a jam nut that way you can just drill a hole into the panel and relpace it. The job will look a lot better if you are able use the panel.

 

4. At this point you realize that it was a great idea to run the middle section instead of running the end of the wire into the car. For the ground use one of the hood pop bracet screws. That should only take two feet of wire. Now get the three wires attached to the switch. Pull the slack from the wire still just chill'n under the hood. Use you last connector to attach that wire to the power of the fan.

 

5. Reconnect the battery. Turn the key on and check for the fan. If she works, make sure EVERY mod wire is safe and in a good spot. Good luck!!!

Awesome! Much appreciated.
Link to comment
Share on other sites

the ac relays are under the hood, all the heavy ga. wore will run between the relay, the fan(switch), and ground. also the power lead from the battery to the relay. then you would have a wire from the relay to the switch. i used speaker wire and powered the switch from the relay.

 

the parking brake adj cover is the piece between the shift console and the center console, the little wannabe cup holder with the coin tray. i drilled a hole in the forward most tray. the terminals were bent at 45 deg so the cover would snap on.

 

you would want an indicator light, or a lighted toggle. if the switch was lighted then you would ground it nearby on a screw.

 

i mounted my switch so that on was toward the seat. that way if you accidentally bump it, you will bump it iff instead of on.

Link to comment
Share on other sites

Didn't read the rest of the thread so I appologize if this has been said here.

 

Common problem, they wear out. My current radiator has 2 dead ones in it and the previouse owner was a moron. Used lots of JB weld to hold them in? They are now permanent parts of the radiator.

 

Originally I wired it all up with a relay, lighted switch, and a fuse.... what a mess. I've since thined the wireing down to just a 15amp switch from battery, to switch, to fan. Keeping some spare switches in my spare parts box in the back of my rig I'm confident in this setup. Ran it thousands of miles like this now on the same switch.

 

Drawback being that you now have to remember to turn it off manualy. That's why I used a lighted switch. One could tie it into their ignition switch circut and have it turn on/off with the ignition switch. I'm not that fancy I guess :)

 

Good luck.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...