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Discussion Starter · #1 · (Edited)
I had installed a Bosh style relay were the stock horn was. It was installed to drive my aftermarket horns. I rode though a rather ominous puddle of water. The relay housing filled with water. I drilled a tiny hole to drain the water out. The relay still clicks when I press the button, but it fails to close the contacts. The horns still work if I short the wires together.

I ordered some replacement relays. They will be here in a few days. For now my bike is not so "horny".

I am not sure what I can do to make the relay more water-tight. Maybe I can put a condom over it. Yes, that was a trick I learned in the military.

Sarcasm aside, I will likely coat the new relay with clear enamel.
 

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I had installed a Bosh style relay were the stock horn was. It was installed to drive my aftermarket horns. I rode though a rather ominous puddle of water. The relay housing filled with water. I drilled a tiny hole to drain the water out. The relay still clicks when I press the button, but it fails to close the contacts. The horns still work if I short the wires together.

I ordered some replacement relays. They will be here in a few days. For now my bike is not so "horny".

I am not sure what I can do to make the relay more water-tight. Maybe I can put a condom over it. Yes, that was a trick I learned in the military.
ha ha...

Harbor Freight and Walmart or any auto parts store sell black RTV in a squeeze tube which can seal just about anything, wipe with acetone then seal it. Can spread it with flat edge knife. Cures fast. Second coat if needed. Heat does not bother it.
 

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Discussion Starter · #3 · (Edited)
35181


There is a slight void in the seal can be seen in the upper right-hand corner. Evidently the water had enough force to enter though that little opening.

The small hole next to the number 85 looks like a "breather hole", but it is not. It is only a dimple. I am not sure what it is there for. Perhaps for alignment during automated assembly.

I installed a new relay. I will throw just a tiny bit of black RTV for good measure.
 

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I had installed a Bosh style relay were the stock horn was. It was installed to drive my aftermarket horns. I rode though a rather ominous puddle of water. The relay housing filled with water. I drilled a tiny hole to drain the water out. The relay still clicks when I press the button, but it fails to close the contacts. The horns still work if I short the wires together.

I ordered some replacement relays. They will be here in a few days. For now my bike is not so "horny".

I am not sure what I can do to make the relay more water-tight. Maybe I can put a condom over it. Yes, that was a trick I learned in the military.

Sarcasm aside, I will likely coat the new relay with clear enamel.
Did you purchase a Bosch style relay or an actual Bosch relay? I’ve used them for years on my cars and the base has always been sealed.

Panasonic also makes waterproof relays used in motorcycles which you can purchase from mouser.

Good luck
 

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Discussion Starter · #5 ·
Did you purchase a Bosch style relay or an actual Bosch relay? I’ve used them for years on my cars and the base has always been sealed.
Last time I saw an actual Bosch branded relay it was the fan relay on my friend's Ford truck. We bought the same part at the dealership. It was $27!

Anyway, I found some with clear housings and an LED across the coil. I can see if water gets in. Hahaha
 

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You need to put the relay out of the elements!
That's why they are always mounted under the seat.
Even if it was a sealed unit I would not put that out in the open - contacts can become corroded!
 

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Discussion Starter · #7 ·
You need to put the relay out of the elements!
That's why they are always mounted under the seat.
Even if it was a sealed unit I would not put that out in the open - contacts can become corroded!
Good plan. I had planned on doing so, but the cable leading to the horn is right there at the front. When I removed the stock horn, I simply replaced it with the relay. There is no good way to move the relay elsewhere without re-routing the wire, or extending it.

I plan to ask a friend to 3D print a plastic box to house the relay so that it can be out of the weather and remain where it is presently mounted.
 

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OR just extend the wires.
Dont be scared of doing that.
Unless that 3D print is out of metal the first rock to hit it right will, crack or break it!
And while I have your attention, I'd guess( dont know) that the horn button that came with the bike already is part of a relay setup, so you're adding another relay?
 

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Discussion Starter · #9 ·
I'd guess( dont know) that the horn button that came with the bike already is part of a relay setup, so you're adding another relay?
Being that there is yet to be a service manual on the 2021 Rebel 500, I have no schematic. I have no quick way to know if there is a relay, or if only the tiny button is switching the horn. I suppose I could just disconnect the added relay and press the horn button, with the ignition key on. If I hear a "click" then well, I will know that there is a relay somewhere on the bike.

The two horns I placed on my bike draw 3.5 amps each. The stock horn only draws about 2 amps. I figured that the switch will fail in short order if there is no relay.
 

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I agree with your statement.
But the way it used to be was the horn button was the smaller wire to energize a relay with the thicker wires to the horn.
Now with all the ECM and software and everything I dont know if that is still true.
At 3.5 amps that is not much of a draw. Since the horn is on only a few seconds at most it should handle the current.
 

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Discussion Starter · #11 ·
I agree with your statement.
But the way it used to be was the horn button was the smaller wire to energize a relay with the thicker wires to the horn.
Now with all the ECM and software and everything I dont know if that is still true.
At 3.5 amps that is not much of a draw. Since the horn is on only a few seconds at most it should handle the current.
I noted that the leads that go to the stock horn are not very big (maybe 22 GA wire). They now go to the relay and it draws, at most, 100 mA.

Being that the two horns combined draw 7A, I did not want to take a risk. Maybe later I will put together a circuit using a MOSFET, and pot it in epoxy.
 
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