You don't see a difference between the bench setup and how it was wired up in the car?

 

A 1N4007 diode should suffice.

I looked it up. this diode is "rated" at 1A. What if my circuit "carries" 2A, or more? And the reed switch? I've already "fried" 5 or 6 of them.
The reason I "stuck" with reed switch is that I saw a video, where the guy used, presumably, only the reed switch, w/o mentioning about any other el. components, like relay, diode etc. and the light turned on and off several times (without "frying"). I just don't understand what's wrong with me. Assuming that the video was true.

 

You don't see a difference between the bench setup and how it was wired up in the car?

wait... the coil "connects" to pos. PAST the light bulb (load). I'll go to the garage and "move' the bulb, to see if the relay buzzes....

 

It won't buzz because it will not activate.

 

update: "rewired" (on bench) it and the relay buzzes....

 

How did you wire it this time?

 

see above message - I edited it with a picture.

 

That's exactly how you have it wired in the car and why it buzzes.
You still don't understand why that doesn't work?

 

Nope ))) what if I wire everything is "reverse"? like so:

 

Will have the same problem.

 

ok.. so, either run a new pos. wire to the fuse, or abandon the whole idea of reed switch and see if I could install a simple mech. switch, like a door jamb type. How naive I was!!! Thank you for your help!!!!

 

Yes, either is the only solution.

 

Thanks and good night!

 

Hi wwdwgs & sghioto,
So sorry I came in late and went off track.
I am sure wwdwgs can incorporate his bench setup ( post # 12) in the existing wiring.
I have included the flyback diode.



Nandu.

 

Update: instead of running a new wire to the fuse, I ran it to the dome light (past the light on the positive wire). Chattering is gone! Just for fun, I wired to the opposite light side (neg) 0 chatter came back. Since the light is closer than the fuse, I will run the pos. wire (from relay coil) to the light's pos. side and will get a new reed switch, as all others are damaged.
Still don't understand how the other person wired only reed switch without relay and not "burning" it.
The chattering problem is solved, therefore I'm not sure that the flyback diode is needed. For now, I think the corrected wiring works.

 

Keep the diode installed across the relay coil.
As long as a reed switch can handle the current the relay is not needed.

 

Can I lower the current (amps) passing through the reed switch with a resistor? Is there a need to lower current for reed switch? will this reed switch last? The reed switch is rated 0.5A, relay's coil - 1A.
The below diagram is how it's wired now and it works, no chattering. The Resistor with the question mark is what my question about.

 

I doubt the relay coil is drawing 1amp.
Most likely it's the contacts that are rated up to 1amp. And if that's the case maybe underrated depending on how much current the lamp draws.
Post a link to this relay.

 

relay: https://www.relayspec.com/specs/099/G8HN.pdf (and also attached picture)
reed switch: similar to this one: https://www.amazon.com/dp/B0BX2ZRZ8T?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1

 

The relay coil resistance is 110 ohms
according to that data sheet.
Divide 12V by 110 = 0.109 amps well below the current rating of the reed switch. No resistor needed.