Jump to content

Is a diode REALLY needed, or do relays have diodes built in????

TheStug
 Share

Recommended Posts

TheStug Enthusiast

TheStug

Posted
Posted

2012 Silverado, 4x4.

 

I'm trying to add a circuit by using relay and the Middle Bus Electrical Connector (Driver footwell). Using Pin 7 (Crank/Run) as signal feed to the relay and pin 1 as ground. Stud 2 on the underhood fuse box for Battery feed.

 

According to the GM Upfitter, they recommend adding 12112422 diode to the relay to prevent voltage spikes to the ECU when the switch opens (interrupts the circuit). I've got random relays from junkyards from Toyotas, Fords, chevys, etc. Do any of these have diodes built in so I don't have to spend like 10 bucks getting a diode? (or a 100 pack... ridiculous) It'd probably be easier to buy a relay with it built in if they exist.

 

I see some people tap into fuse #43 but I'm sure GM would frown upon that and seems it could cause some gremlins so I'm not going to tap into the underhood fuse block.

 

I'm wanting to use it to power a wideband O2 sensor (HPTuners).

 

In Cab switched power

chem_man Enthusiast

chem_man

Posted
Posted

I googled the part number and found out the diode's specifications are 400 VDC and 3 amps.  Therefore it is a 1N5404 silicone diode that can be purchased for about $0.25 at the right place.  Since Radio Shack is no longer in business, you could check with Affiliated Electronics there in Tulsa.  Ask them if they have either the 1N5404 diode, or the NTE5804 diode.

 

You can also go to https://www.ntepartsdirect.com/ and order it directly from them (I don't think they have an order minimum).

 

You can also call around to TV repair shops if there are still any open in Tulsa.

 

Spoiler
Spoiler

 

 

 

TheStug Enthusiast

TheStug

Posted
  • Author
Posted

Before even seeing your response, after a couple days of internet research, that is exactly the same part I came up with. I was constantly worried I would get the wrong type of diode... I ordered 20 of that and cost me about $16 with shipping.

 

Hopefully this helps someone else in the future with the exact same questions.

 

Now to figure out how to wire everything up so the diode is easily replaced in case it is ever damaged

 

Thanks!

  • Like 1

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • KARNUT
      Gas Prices

      By KARNUT · Posted

      3.19 @ Kroger’s in Montgomery Tx
    • Flynlow
      2027 Chevrolet Silverado: Official Discussion

      By Flynlow · Posted

      We have now!  2027 GMC Sierra  Early look, but I'm a GMC guy and so far I think I like the looks of the Chevy better.
    • newdude
      Lower trims ( WT, Custom, Silverado ( aka LT )

      By newdude · Posted

      HD at the moment, are kinda their own deal.  How LTZ sells on those vs on 1500, there is a difference.   They are merging most of the mid trims on 1500.  LT, RST and LTZ are replaced by one trim, Silverado.  LT and RST are a BIG portion of sales.    Bad naming choice aside, the new Silverado trim will offer the spread of options that those three trims offered.  So expect to see things like the tech package for example, and memory seats.  And LT Trail Boss will now just be "Trail Boss" (formerly LT Trail Boss) but will offer content spread like the new Silverado trim will.  The press photos showed the Trail Boss (formerly LT Trail Boss) has access to Super Cruise now, which on the current truck was High Country only.       Here is the Trail Boss interior.  Memory seats and Super Cruise are present.  All things the LT Trail Boss it replaces, and the RST it was based on didn't get on the current gen.  You had to go to LTZ or ZR2 for memory seats, and High Country for Super Cruise.      
    • dennismc
      2021 vs 2026 handling (1500 X31 Sierra)

      By dennismc · Posted

      I installed a Hellwig rear sway bar on my 21 Sierra SLT, it made a huge difference on how the truck handles, no body roll, the trucks much more planted now. Not sure of the suspension differences between the 21 and 26,  if its body roll your having a sway bar will solve it. 
    • Old Bay
      frustrating P0446 code

      By Old Bay · Posted

      So a follow up and my fix. I found in online searches the live data to look at on a scan tool to verify the fuel tank pressure sensor was working.  It showed an spec number towards the lower end of the rang, but in spec.  Then while it was running opened the gas cap and the pressure should change.  It didn't change even a tiny bit.  The data for the purge valve said it was open...never changed. So then I measured the voltages on the plug for the fuel pressure sensor and they matched what it should be.  So local car quest parts had the sensor in stock...it was a bit of a pain to remove and an even bigger one to get it to actually go back in.  It helped to unbolt the driveshaft and bungie cord away from the gas tank to give a bit more room to work. So fuel tank pressure sensor in I cleared the code, and started it up.  I went to the scan tool's live data and... Eureka! The pressure number was different and fluctuated a bit.  So took it on a short drive and pressure number varied saw the purge valve go from closed to open and back to closed.  Drove it to and from work for roughly a week plugged in the scan tool no codes.  I took it in to get tested and passed.  In my state's infinite wisdom (oops meant greed), since I pushed the test with the maximum extensions I have to take it back in by Feb '27 to 'get it back up to date', then my next test won't be until Feb '29. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...