Two-Stage Switch

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=31361
Printed Date: May 10, 2025 at 8:35 PM

Topic: Two-Stage Switch

Posted By: caifansc
Subject: Two-Stage Switch
Date Posted: April 30, 2004 at 9:37 PM

I want to see if its possible to independently control the low and high speeds of a fan through a a single momentary switch. I was thinking that maybe with some relays it would be possible to turn on the low speed of the fan, and when pushed again the high speed would kick in, and the low speed off, and with a third push of the button the fan would cut off. Is this possible? The only restriction is that the switch is a momentary switch attached to a HURST T-handle shift knob. Any help is appreciated!

Replies:

Posted By: caifansc
Date Posted: May 02, 2004 at 7:54 PM

anyone? i know somebody has a suggestion out there!

Posted By: Teken
Date Posted: May 03, 2004 at 3:40 PM

Short answer = No . . . Based upon what you have written above.

Regards

EVIL Teken

Posted By: caifansc
Date Posted: May 03, 2004 at 3:46 PM

Well, the problem would not be regarding the fans...i guess the problem exists in the switch correct? I would guess that trying to use one switch is what makes it impossible.

Posted By: Teken
Date Posted: May 03, 2004 at 3:58 PM

That would be correct . . . If you are not constrained to the original switch. Then anything is possible, and you may control the unit as you discribed.

There are dual position switches on the market, weather they be rotary, or a dual position toggle switch.

It is up to you, whether it is worth the time and money to do it though.

What is the reason for this ability??

Regards

EVIL Teken . . .

Posted By: caifansc
Date Posted: May 03, 2004 at 4:06 PM

I thought so Teken...well, the reason for the constraint is because the switch is attached to the shifter knob...and im not sure if Im able to change it. For all i know it might be sealed inside. I've seen DPDT toggle switches, but have not seen any rotary switches....do you have any info on these? I have not bought the shifter knob yet, so perhaps i might go another route and just mount a different switch somewhere else in the car...in such case i would still need help with how to wire this...so if you school me in how...i'd be greatly appreciated Teken.

Posted By: Teken
Date Posted: May 03, 2004 at 4:15 PM

All you would need is a 4 position rotory knob style switch.

The wiring for it would be very straight forward. I will simply explain the switch first, then we can do the relay later, so we are both on the same page.

1. The first position would be off.

2. The 2nd position would be to turn the low speed on.

3. The 3rd position would be to turn the hi speed on.

4. The 4th position would be to turn on the two together

The interior rotory switch would be a used as the ground to *turn-on* the fans. And not to power the fans on or off. Simply the ground to initiate the flow of current to the relays. This makes the circuit safer for you and the circuit, incase of a short circuit.

If you havent bought any relays yet, you will need a few, and if you intend to install the relays in the engine bay, then you would be asked to purchse the water sealed units which have a extended housing to protect the female end of the plug.

Let me know if you want to go further...

Regards

EVIL Teken . . .

Posted By: Teken
Date Posted: May 03, 2004 at 4:28 PM

You know I must be too tired . . . I will have to stop writing you untill I get some sleep.

I just realized that I stated you could control the two fan speeds, when there is in fact only one fan, and not two.

Sorry, please omit the 4th position, as that would be impossible to do with one fan. posted_image

EVIL Teken . . .

Posted By: caifansc
Date Posted: May 03, 2004 at 7:49 PM

Yeah, its only a single two-speed fan...so step 4 woudlnt apply. I follow you up to now Teken. I have a few questions so far...1, do you have any model #'s for rotary switches so I can start looking into them (sizes, etc)? 2, you mentioned water sealed relays to use inside the engine bay...whats the difference between them? Thanx!

Posted By: Teken
Date Posted: May 16, 2004 at 10:58 PM

The exterior relays have an extended cover which drops further then the basic interior relay.

If you had a standard relay in your hand, imagine an extra half inch of plastic shroud covering the 5 pins.

When it is mated to the other end of the female wiring harness and applied with the appropiate grease, the unit is very much water resistent.

It is not water proof, though. I will do a search for a rotory switch on the net for you on Monday.

Sorry I did not reply earlier, I did not hit the *e-mail me of replies* button.

Regards

EVIL Teken . . .

Posted By: caifansc
Date Posted: June 01, 2004 at 1:14 AM

Hey Teken...any news on the rotary switches? I've read up on them and tried to find a suitable one for my auto aplication but I find different ones...and of various prices. Im a bit confused as to whcih to get

Posted By: iskidoo
Date Posted: June 01, 2004 at 1:45 AM

I'm still curious as to why you want to control fans from your shifter knob. Are the fans for heat/AC?

Posted By: caifansc
Date Posted: June 01, 2004 at 2:11 AM

They are for cooling the rad. The factory settings for the fans to kick in are controlled by teh EEC on my car and, beign supercharged, it needs to stay cooler than what the factory settings allow. I want to bypass the factory settings and just control them from a switch...i was thinking of having them controlled by a momentary switch on a hurst t-handle shifter knob, but have now decided to keep the stock look and place a rotary switch in my ashtray with at least 3 positions to control the low speed, high speed and aux. pusher fan.