Help wiring for born blast when locking doors

Sorry if this is in the wrong spot. I just installed a horn set up in my truck yesterday. I have it wired into my stock horn with a switch to where I can turn my air horns off and have my regular horn or vise versa. The problem I have is that when I have the air horns switched on my keyless entry won’t honk the horns but when I switch it back to factory horn it beeps it when locking. I have a 2000 gmc Sierra with factory keyless if that helps.

We would need to know how you have it wired to the stock horn…
Did you cut the horn wire and insert a SPDT switch?
If it’s like this diagram, I don’t see why it doesn’t work:

Welcome to the forum.

I have a on/off/on switch wired in. It is almost like the keyless entry function isnt working when i have the train horn flipped on. I cut into the wire right at the horn and ran it to the valve.

Have you checked the switch and all the lines for continuity? It should work if wired liked the schematic ear2ear posted.

I imagine that the pulse duration from your alarm is very short (milliseconds). Depending on the type of solenoid you’re running, it could be that the duration of the ON state is just too short to throw open the valve. You can try using a solid state relay on the horn circuit and having the horn solenoid wired directly to a good power line. That way you can be assured the solenoid will have maximum juice to throw open.

Also, check the type of resistance you have in the switch. Some switches (e.g. with back lighting) will draw extra power (i.e. higher resistance) and won’t allow enough current to flow through to the solenoid for it to quickly trigger on and off.

It seems like the keyless feature doesn’t work when the switch in flipped for the train horn

?? … so can you reconfirm the issue:
a) Your doors aren’t unlocking when you have the switch flipped to train horn; or
b) your horns aren’t sounding with the unlock/lock of your doors?

If it’s (b), then see my previous post.

I’ve been away from electronics too long or I would have remembered stuff like this.:o

mine the same way too.

my set up is a relay. press the horn button twice on the key and it will beep the stock horn, and theoretically, the signal wire that is tapped into the positive stock horn wire will send the pulse to the relay, opening the relay, thus sending power to the solenoid to open.

the problem is the horn beeps for such a short period of time it cant open the relay long enough to send power to the solenoid. however, the train horn will sound when the actual alarm is set off because the stock horn is beeping for a longer period of time allowing the chain of events to happen fully.

personally i like it this way. i like to make sure the car is locked by pressing the lock button twice and beeping the stock horn and not worrying about the train horn going off because of the attention it will attract. i dont want some pissed off guy doing something to my car.

so tom, i bet if you set the alarm off the horns will go with it.

also if i button mash the lock button on the key, you will eventually hear a little, “meep” which is the valve opening a little, and letting just a tad of air to the horn.

When you have switch flipped so train horns work you still need to activate streeing wheel button to activate solenoid. Streeing wheel completes the circuit. In stock horn mode there is a relay that is in use with keyless entry,at least that is what I was told and it does make sense.

I’m bringing this thread back. I wired my horns the way described in the first post but the honk on lock isn’t long enough to open the valve all the way. I can hear the solenoid clicking but no noise. Any idea how to get it working if possible?

Find the wire that is sending the audio command from the locking module to the horn. If it’s a 12v short burst signal, try putting a small capacitor on that line (e.g. 2200?F). Failing that you will need to buy or build a little timer latching relay circuit.

Good idea! I’ll do some research on capacitors. Thanks.

I had this problem on my Honda. I was able to fix it by simply wiring a relay up so that way the solenoid has max power running to it. Only problem I am having now is sometimes I forget the switch is on for the K3’s and when I am locking they like to give a nice audible “HONK” when I hit the lock button twice. he he he