i got a DPDT switch that i had wiried up to control my efan......i removed the wires and didnt pay attention to were they go....

i have these wires going to it:
3 constant hot
1 wire from the purple HVAC wire
1 wire to A/C demad wire to the efan controller
1 + in run to the controller

up position = forced on
center position = off
down position = auto

HELP!

 

bump

 

bump again....

does anyone know the wiring schematics of a DPDT switch?

 

Wish I could help but I don't speak that language.

 

I don't know if you're using a toggle or a rocker, but it doesn't matter...the back still looks the same.

Ok, based on the picture below, if "up" was moving the toggle towards A and B, the below connections should work the way you want. If its a rocker switch it would be like tilting the rocker towards A and B.


A: Constant +12V
B: Purple HVAC wire
C: +12V in run to fan controller
D: A/C Demand to fan controller
E: Constant +12V
F: Constant +12V

What this means is that when you move the switch towards terminals A and B, C shorts to E and D shorts to F. When you move the switch the opposite way, C shorts to A and D shorts to B. Any position other than off gives 12V to the fan controller to enable it through terminal C. When you move the switch in the "on" direction you give 12V to the A/C demand line of the controller through the D terminal to force it on, and the "auto" direction just gives it the usual A/C demand signal.

 

wow! if this works (from what i have seen you post on wiring before, i am sure it will) you da man!

 

You're welcome, but now I have something to live up to...oh the pressure...

Also, unless you really want to be able to run your efan with the truck off I would suggest changing the constant 12V wires to 12V in run...no chance of you killing your battery that way...plus I just like having as few things powered as possible when I'm away from my truck, especially if it isn't fused.

 

yea i am going to change that because whenever the truck is off and the switch in "auto" mode, the fan comes on.....can't figure that out, but it does....

the 12v+ wires i always fuse....no matter what......

on something like that, what size fuse does it need to be on the 12v+ to the switch? i have a 30A, but i think it is way too big...i was thinking something like a 10A or 15A...

 

You should have 3 wires of interest going to your fan controller...a constant 12V, a 12V in run, and an A/C demand. The reason your fan comes on when the switch is in the auto position is because it is still supplying 12V to the 12V in run wire going into the fan controller. Whenever that wire has 12V on it the controller will switch the fan on if the A/C demand wire gets 12V, or if the temperature gets to the set point. Think of it like an enable signal for the fan controller. Even through the fan controller will never see 12V on the A/C demand wire when your switch is in auto and the truck is off, it can still come on at any time if the temperature is high enough because it is still enabled.

The power the fan draws should be coming to the controller through a big constant 12V wire going to the battery. The 12V in run wire that would be going to the terminals on your switch isn't going to be powering the fan, so I would think a 1A-3A fuse would be fine...it really depends on if that wire directly drives a relay or something. 10A would be too much.

 

the fan comes on with the switch in Auto AFTER the truck is shut off....it works like normal with the ignition on ACC or with the truck running....

i am going to change the location of the + wire going to the switch to a switched spot in the fuse panel and see if that helps.....

 

Yea, thats what I thought I was saying. Even though the truck is off, you are still giving it 12V to keep the controller on...so the fan can come on if the temp is high enough.

 

no it comes on no matter what as soon as i shut the ignition off, no matter what temp the controller reads......

i have the temp sensor in the controller wired to the PCM coolant temp sensor (since i have an AutoMeter sensor in the stock gauge sensor location).....

BTW: i have the SPAL FAN-PWM controller....

 

oooooh...I see...yea, that's odd. The PCM and fan controller probably just don't like sharing the sensor...so it looks different to the fan controller when the truck is off. Getting rid of that constant 12V on the switch will fix it so meh.

 

yea hopefully........