Please Help with Switch/Diode Question

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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=18756
Printed Date: July 14, 2025 at 4:22 AM

Topic: Please Help with Switch/Diode Question

Posted By: rgardjr
Subject: Please Help with Switch/Diode Question
Date Posted: September 10, 2003 at 2:58 PM

Well I've got a question for anyone with some electronics expertise. I purchased a PAC AAI-GM12 auxilary input for my truck. I don't like the toggle switch that came with it and I'd like to replace it with a lower profile rocker switch. The problem is that I don't have a DPDT on-off-on rocker switch to replace it with, but I do have a SPDT on-off-on switch I'd like to use. I thought that I might beable to accomplish this with a diode, but have no real experience with them. Here is what the original switch looks like:

posted_image

The thin black line is a jumper that jumps those 3 poles on the switch together. From what I can tell when the switch is flipped in one position it connects all 3 together Black-Red-Grey. When flipped in the other position it just connects the Red and Black. I thought I could accomplish this on a single pole switch with a diode like this:

posted_image

Any ideas if this will work? If so what value of diode would I need? Thanks-Rick

Replies:

Posted By: the12volt
Date Posted: September 11, 2003 at 4:24 PM

Hi Rick, if the red wire is 12V+, then yes, the black wire will have 12V+ in either position. The value needed depends on the amount of current draw that exist on the black wire.

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the12volt • Support the12volt.com

Posted By: rgardjr
Date Posted: September 17, 2003 at 1:29 PM

the12volt wrote:

Hi Rick, if the red wire is 12V+, then yes, the black wire will have 12V+ in either position. The value needed depends on the amount of current draw that exist on the black wire.

Thanks for the help. I bit the bullet and ordered a DPDT switch-just like the one that I replaced except in a rocker style. With the internet it ended up being pretty easy to find one. BTW Mouser doesn't have a $25 minimum on parts orders for anybody looking to buy a couple of parts for a project.