wiring question

[enjenjo]

2. If the vehicle has a computer controlled engine, or BMC, it would be prudent to use a relay with an internal diode across the coil to suppress the high voltage spikes generated on release of the relay.

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How do you identify a relay like the one you suggest and where would I purchase one?

Del City has them. as well as Waytec. I would bet that Haywire has them too. Just ask for a relay with a diode.

[WZ JUNK]

So the diagram on the case should look something like this if it has a diode.

I guess I need to change out the ones on my 54 Chevy with the throttle body computer and install the ones with diodes.  I will see what I find locally.

I found these on Amazon.  Not a bad price.

https://www.amazon.com/Ehdis-JD2912-1Z-12VDC-Vehicle-Automotive-Switch/dp/B01IX7NV0C/ref=sr_1_5?crid=3AH8DPANNT6NR&dchild=1&keywords=auto+relay+with+diode&qid=1590942676&sprefix=auto+relay+with+did%2Caps%2C275&sr=8-5

[kb426]

I learned something new! I found this page that clarifies some of the reasons to use or not use a diode relay.
https://electronics.stackexchange.com/questions/56322/do-i-need-a-flyback-diode-with-an-automotive-relay

[Fat Cat]

Here is my attempt at how I would wire it.

Only two comments.
1. If the relay coil supply is connected to the downstream side of the fuse rather than directly to the battery, (or jumpered at the relay),  then all the wiring is protected.

2. If the vehicle has a computer controlled engine, or BMC, it would be prudent to use a relay with an internal diode across the coil to suppress the high voltage spikes generated on release of the relay.

So much correct here. In my defense I originally drew this up at about 3-4am. I was intending to put a 2 amp fuse in the line for the 85 terminal but forgot it. This was after I drew it originally with it jumpered from the 30 terminal. I did not mention the diode because I generally used the diode versions in the work I did at the RV place. So I just assumed its use. but it is worth mentioning. Thanks for keeping me on the straight Peter.

[timkins]

If as Fat Cat suggests that I can jumper between terminal 30 and terminal 85 can I solder these two together and then run a single wire to the positive post of the battery with an inline fuse installed?

[Bruce Dorsi]

If as Fat Cat suggests that I can jumper between terminal 30 and terminal 85 can I solder these two together and then run a single wire to the positive post of the battery with an inline fuse installed?

Yes.

[timkins]

Thank you

[timkins]

Thank you to all who responded. Got the relays installed without a problem thanks to the drawn diagrams and I learned something in completing the job.