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

[TheStug]

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]

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]

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!

[chem_man]

_{Slip the diode into some heat shrink tubing before soldering it in place.}