Horn Heater Relay on Datsun 620 keeps clicking. When I unplug it, nothing bad happens. What is the purpose of this thing, and why is it clicking?

[Datsun_620_Stock]

I have a 1974 Datsun 620 (manual transmission). Thanks to the wonderful guide that @datzenmike and others contributed to (link here: https://ratsun.net/topic/77853-alternator-upgrade-questions/ ), I was able to successfully upgrade my alternator to an internally regulated 35 amp alternator off a '79 620. It swapped in perfectly and I bypassed the old external voltage regulator system using the instructions in the above guide. I made sure to solder a few connections as Mike described to avoid power draw when the vehicle is off.

But this got me thinking... ever since I bought this truck, the horn heater relay (I think that's what it's called) clicks frequently whenever I am driving. This has always been the case, even before I did the alternator swap. The relay I am talking about is behind the ash tray, inside the cab. The part number is: "25230-89924".
Here is a picture:



This thing clicks randomly, all the time, whenever I go anywhere.

I have previously disconnected it, to see what would happen, and drove hundreds of miles. Nothing bad was observed. The vehicle worked flawlessly, the horn and heater still worked perfectly. I didn't observe any differences in the vehicle.

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It should be noted that the electric choke on my aftermarket carburetor is NOT hooked up and has never been hooked up. I have a manual choke hooked up only. You can see a photo of what my carb wiring looks like below:



The question is:
Is it ok to unplug the horn heater relay? Will it be a problem for me later on? What future functions do I "lose" by keeping it unplugged?

Bonus questions:
A: My truck always diesels when I turn off the key. I assume the anti diesling wiring is not connected to the anti-diesling solenoid properly? It would be nice if it worked, rather than putting it in 4th gear every time I park. It has always diesled ever since I bought the truck.
B: Ever since I upgraded alternators, my "charge light" in the dash flickers when my truck diesels, whereas before, it went out as soon as I turned the key off. I assume this is the new normal and expected behavior?

 

[datzenmike]

25230-89924 is the BCDD solenoid relay. (boost controlled deceleration device) If clicking it's working and doing it's job resetting the BCDD on the carburetor. Does your speedometer read down to zero or is it 10 MPH?

 

A  If the anti dieseling solenoid (AKA idle cut) is disconnected, the engine won't idle below about 1,100 RPMs. Make note that if your idle is set too high it will diesel regardless of the idle cut solenoid. The solenoid when energized allows fuel down to the idle circuit. When ignition is turned off it cuts the fuel, stalling the engine. There are two wires going to the back of the carburetor. A Blue one for the choke heater and a Red one for the Idle cut. It's possible that it's connected but someone removed the solenoid and took the internal parts out disabling it.

 

B  Solve the dieseling and you solve the flickering light. LOL.

 

[Datsun_620_Stock]

12 hours ago, datzenmike said:

25230-89924 is the BCDD solenoid relay. (boost controlled deceleration device) If clicking it's working and doing it's job resetting the BCDD on the carburetor. Does your speedometer read down to zero or is it 10 MPH?

 

A  If the anti dieseling solenoid (AKA idle cut) is disconnected, the engine won't idle below about 1,100 RPMs. Make note that if your idle is set too high it will diesel regardless of the idle cut solenoid. The solenoid when energized allows fuel down to the idle circuit. When ignition is turned off it cuts the fuel, stalling the engine. There are two wires going to the back of the carburetor. A Blue one for the choke heater and a Red one for the Idle cut. It's possible that it's connected but someone removed the solenoid and took the internal parts out disabling it.

 

B  Solve the dieseling and you solve the flickering light. LOL.

 

Thank you @datzenmike. Regarding the speedometer, the lowest number listed is 10mph. Does this make a difference? Here is a picture:

 

To be clear, I drove for about 1000 miles with the "BCDD solenoid relay" (2523089924) unplugged, and the vehicle drove no differently than before. It idled fine and I observed nothing different. In fact I have it plugged back in now. Still no noticeable difference.

 

Regarding the wiring to my aftermarket carburetor, there is nothing plugged in to it. Zero. No electrical whatsoever. Here are some photos of the wires:

 

Photo 1:

 

Photo 2:

 

You can see how many of these wires are just hanging, disconnected.

 

My carb has a manual choke attached, and that's it.

[datzenmike]

The 10 MPH speedometers have a switch that turns the BCDD off or resets it. The idle is very slightly fast when the BCDD is active and when slowing to a stop in gear you may notice that at 10 MPH the idle suddenly drops. Or not. 

 

The red and blue wires come from between the coil and the left headlights. They pass the distributor and near the intake the White/Blue on the harness plugs into the Blue wire going to the choke and the Yellow/Red plugs into the Red for the idle cut.