Fan wiring diagram help please

[chuzie]

Here is my drawing of the fan system I am doing. I have run into a snag with the two diodes that are to help prevent either of the two temp switches from actuating the fan of the opposing system.

The diodes, in their depicted configuration, block all ground signal when I actuate the switch to force the fans on via ground (not my intention).

When I flip the diodes, the fans turn on, of course, but actuate each other as well instead of independently.

I was not aware I could only use a diode in a voltage only scenario. Any suggestions for fixing this issue?

 

[Steve83]

That diagram is VERY difficult to read, and incomplete. You don't have the source for "IGN" (which I assume is a 12V source), or the internal wiring of what I assume is the main control switch near the top center.

While you're adding that to a new diagram, take a look at this & the NEXT few:

 

[chuzie]

You are right, I should have shown my work properly. I have a bad habit of making assumptions in my diagrams. Posted a better pic though.

That controller is just a DPDT switch. I drew it that way for simplicity albeit not technically correct for a diagram.

Anyway, I think I may have found a solution though it is going to require me to rewire a lot of the system already in place. Basically I shifted from a (-) trigger to a (+) trigger at the temp switches.

AUTO - Fans operate independently via their respective temperature switch
OFF - Fan are forced off regardless of temperature switch input and RED LED is illuminated
ON - Fan are forced on regardless of their respective temperature switch and ORANGE LED is illuminated.

 

[pcf_mark]

My brain is cooked a bit from trying to figure this out and articulate it. I think you made it too complicated. Wire each sensor and relay independently to control their individual fan. They get power from the battery directly. The control relay get switched 12v on one side and the sensor on the other. When the sensor hits temp wire is grounded, relay closes one fan runs. Do this for both circuits.

The switch is your master over ride if you will it needs to be double pole double throw. In one position is says "no matter what I want both fans on" OR "no matter what I want both fans off" OR "work automatically". To make this work the wires going to the sensors need to be redirected to the switch center poles and not directly to the sensor. Then one side of the switch terminals goes to the sensors (individually). In one switch position the circuit works exactly like above it just passes through the switch first - automatic mode. In the center position the circuit is interrupted and nothing will come on - off mode. Then ground the other set of poles (individually). In the third position the sensor wires will be directed to ground turn them on.

 

[pbwcr]

Steve,
Just been searching for a 170f Sw and had no success. Thanks for the call out.
You did not mention the source for the 210f unit any help on that one?
Thanks, Paul
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That diagram is VERY difficult to read, and incomplete. You don't have the source for "IGN" (which I assume is a 12V source), or the internal wiring of what I assume is the main control switch near the top center.

While you're adding that to a new diagram, take a look at this & the NEXT few:

 

[Steve83]

AUTO - Fans operate independently via their respective temperature switch
OFF - Fan are forced off regardless of temperature switch input and RED LED is illuminated
ON - Fan are forced on regardless of their respective temperature switch and ORANGE LED is illuminated.

I think you're overcomplicating this by trying to combine 2 independent fan systems into 1 switch. Buy some simple, small, automotive switches, and mount them intuitively so each fan is on its own switch. Here are some switch panels I've built:

. .

...the source for the 210f unit...?

My junkpile. :-[ It was in a bag with an ACDelco card, and a pigtail. I can try to look for the card, but I'm not sure I kept it. I might have gotten it from a friend, or a garage sale, or a swap meet, or a clearance bin at a parts store, or a junkyard, or... You should be able to find plenty on Amazon & eBay.

 

[chuzie]

Thanks guys. Time to get to work. ;-)

 

[pbwcr]

It was in a bag with an ACDelco card, and a pigtail. I can try to look for the card, but I'm not sure I kept it. I might have gotten it from a friend, or a garage sale, or a swap meet, or a clearance bin at a parts store, or a junkyard, or... You should be able to find plenty on Amazon & eBay.

======
Now after a search now I came I empty for the 170f switch. Can you help with a part number? The 210 F is common and not an issue.
Thanks, Paul

 

[Steve83]

I just collect them at JYs.