Hella Horn ?

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nspctr1

nspctr1

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Location
San Antonio TX
So, I'm tired of the stock horns wimpy sound so I picked up a pair of hella super tones for my 40. I am going w the stock relay and just installed horns in stock location. After connecting everything I set the horns off and only the ps works. I checked the connections and the d side horn reverbs it doesn't sound. I swapped connections and same problems.
Any ideas?

Thx

Kevin
 
I checked the horn with the battery and it works fine. I did switch pos and neg, reenforced ground in case not making good contact thru frame and the horn just kinda vibrates for lack of a better term. Not sure if it could be a relay issue since it fires one side which tells me it is functioning.

I ran a jumper from the ps side horn pos to the ds side pos and it just vibrates again. Ground is still enforced even though made through ground connector.
 
My 0.02 Cents....

Those new horns draw more current than the old ones.
The OEM set up runs from the battery to the fuse box to the relay to the horns all with the thin OEM wiring. At the end there is not 12V left.

On my truck my new horns only worked when I revved up the engine.
In other words when there was 14.8 Volt on the system so around 12Volts at the horns.
I ran a new wire with a in line fuse directly from the battery to the B terminal on the relay.
Problem solved! Now the whole neighborhood knows that I have new horns.

Rudi
 
Last edited:
bj40green,

Now this is another great idea from you. Going to be on this tomorrow.

Thanks, John
 
This is exactly why I use the next higher gauge wire on some circuits when i build a new harness. Toyota, in my opinion, didn't account for 40 years of heat, flex, terminal wear, and corrosion when designing the harnesses (of course who does?). The voltage drops in an old harness can be significant.

Rudi, that IS an excellent suggestion to remedy the problem without re-wiring the whole circuit.
 
I'll see if Rudi's suggestion works. Would replacing the relay help?
 
nspctr1 said:
I'll see if Rudi's suggestion works. Would replacing the relay help?
Click to expand...

I would do Rudi's suggestion. Just got through doing it myself. Took 15 mins and totally solved my issue, which was the exact same as yours. ie lame sounding Hella horns.

I've had the same set of Hella trumpeter (sp) air horns for maybe 15 yrs. Year by year they get more lame. From time to time I clean things up, bought a new OEM horn relay...all this helps, but over time it always reverts back to being lame. And every time I checked the horns directly to batt post they worked great/loud. So it had to be the old wiring...and in my case it was. As he suggests...use an in-line fuse.

Thanks, John
 
Can u take a pic or draw up something that shows the tab to connect Hotwire to

Thx
 
nspctr1 said:
Can u take a pic or draw up something that shows the tab to connect Hotwire to

Thx
Click to expand...

Lets see if this will help. Mine is a stock 2/75 40 with the oem horn relay on the pass/side fender well next to the coil.

I took an in-line fuse from the batt pos. to the green w/red stripe wire of the horn relay. That's it !

If you don't have stock wiring at the horn relay, just take a test light & find the constant hot wire at the horn relay bundle. Only 3 wires go into the relay & my hot wire was the green/red.

This way, my multi meter said 12.8 to the relay w/engine off & 14+ w/engine running. Before I did this, sometimes I could not get any horn w/engine off.

Let me know if this isn't clear.

Thanks, John
 
Let's see if this makes things clear.
The wiring diagram.
Disconnect the Green/[STRIKE]White[/STRIKE] Red wire to the B terminal on your relay. Fold double, isolate, put away in a dark corner or so :).
Here is the new situation
horn relay crop.webp

As said before: buy an in line fuse.
I used this one. You have to cut it somewhere. I did that in the middle.
Crimp a terminal on one side (I used a ring terminal) and hook up to the battery + post.
in line fuse.webp

Connect the other side to the B terminal of your horn relay.
If the wire is too short make an extension.
This pic is from my BJ40. We (diesels) have all the electrical stuff on the DS so use this only as an example.
DSC01815 text.webp

Don't forget to insert a fuse in the fuse holder :).

Questions? Let us know.

Rudi
horn relay crop.webp
in line fuse.webp
DSC01815 text.webp
 
Last edited:
nspctr1 said:
I'll see if Rudi's suggestion works. Would replacing the relay help?
Click to expand...

I'm afraid not (there is a 2% chance that the relay is the culprit), it's a power loss thing. The old horns pulled 7 Amp each. The new ones a bit more. The Toyota wiring is what we call on the "small/thin" side. So the best solution is to run a new feed from the battery.

Horn info.webp

Rudi
Horn info.webp
 
Last edited:
Awesome. Going to do this tonite weather permitting

Thanks everyone
 
UPDATE:

So, I connected everything temporarily, checked the voltage at the relay prior to connecting to battery and have 9.6 volts. I connected a jumper to the relay and got 12.6 w/o engine running. Should be enough to fire both horns. Only PS side worked. May be a bad wire in the loom that runs from the ps horn to ds. I will try and ohm it out and see where the problem is. OR, connect 12v to it and see if it transfers from one side to the other.
I cant run one horn as they sound cheesey alone by themselves.
 
Sounds good (pun intended).

Thanks, John
 
OK
SO, I'm back on the horn issue. I got busy and left it alone after all attempts failed. Now I have the 4th to work on it.
I ran the hot per Rudi's instruction and nothing. I can connect the horns direct to battery and they work so it's not a horn issue. My guess is it's the relay however, when I hook the Grn and Red wire to the hot the relay clicks, when I hook it to one or the other wires that horn honks. I've taken direct wires and tied them into the ground on the battery. No workie,

SO, I took the stock horns and reconnected them and the relay only clicks. I have a new battery and everything works as it should. Except the damned horns....

Ideas?

Thx
 
Ok, If it's not the wiring and not the horns than there is only the relay to blame.
Probably bad contacts. Can you open the relay?
Clean up the contacts to make them nice and shiny.
If not buy a new horn relay. They are not expensive.
Just check that the terminals are marked B H and S.
B = Battery, H = Horn(s) and S = Horn Switch.

Rudi
 
stock relay, wont crack open. I do have the one that came w/ the horns. Do you have to cut the stock plug off and use the stock wires/solder on new blade fittings and stab it into the new relay?
If the old relay is bad, why does it click when power is applied, honk when the grn/ylw wires are hooked to hot? Horn buttons are clean/operational.

I'm confused....
 
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