Weird Horn wiring issue (wire keeps breaking blinker cancel tab!)
 

Hey guys, title pretty much sums it up. My horn was inoperable when I got the car. Added a Momo prototipo with Momo hub (and an offset adapter that positions the wheel a little higher up when steering straight ahead), and started investigating why no horn. Turned out there was no relay! Replaced the relay, threaded the horn wire into the hub through the little hole in the hub (which I'm assuming is the purpose of this hole!), and wired it up. Horn worked great! But then "crack" at first turn of the wheel, accompanied by no more blinker cancel. Took everything apart and sure enough, the horn wire wrapped around the base of the steering wheel (near the splines) and broke the cancelling tab on the wheel (oem cancel ring transferred to the Momo).

I've now wired it up three times using different wiring routing through the steering wheel column, all with the same damn result. Once the force of turning actually pulled my wiring out from the crimp connection, the loose wire grounded against the hub, and I had a fun SUPER loud constant horn in the neighborhood until I could pull the relay. Yes, all the neighbors came out and I felt like a total as_hat. I couldn't get that relay out fast enough...it was like one of those nightmares you had when you were a kid where you can't get your fingers to move fast enough to open a locked door with a monster about to devour you from behind! (ok, maybe I wasn't a kid when I had that dream the last time!).

Anyway, I'm either totally dense and missing something obvious, or there is some secret trick to wiring up an aftermarket horn button! Help, I'm running out of jb weld for my cancel tab! Thanks in advance!

Have you seen this thread?
http://forums.pelicanparts.com/porsche-911-technical-forum/138526-idiots-guide-momo-prototipo-install-carrera.html

Or this one
http://forums.pelicanparts.com/porsche-911-technical-forum/947198-momo-steering-wheel-install.html

Thanks! Yup, read both of those in my quest to see what I had done wrong. Weird part is that I routed the horn wire just as the poster in the first linked thread...through the hole in the hub. If you think about it, as you turn the wheel (and thus the hub) the wire is going to be pulled in the direction of the turn. Then, when you turn the wheel back, at least in my set up, there will be extra slack in the wire from being pulled into the hub and somehow that wire, at least in my set up, will eventually interfere with the cancel tab of the horn ring, which then snaps off. I can't see how to keep this from happening, which is why it is so weird to me that no one has ever mentioned this issue on the forums (at least as far as I could find in a pretty in-depth search).

Can you post some pictures showing how you routed the wire from the steering column to the associated hubs and how the wires are connected? I'm having difficulty visualizing how you did it that would result in the problem you have.

I will definitely do so tonight....really appreciate the help. In the meantime. I'll try to explain a little better:

There is a brown wire with white stripe coming out from the left side (top) of the steering column. It appears to originate behind (or even at) the turn signal switch assembly. Installed a spade on that wire and threaded it through the hole drilled in the top left (driver side) side of the hub, and connected the spade to the connector on the horn button. Seated the horn button, everything works fine when button is depressed.

Then go for a drive and the wiring gets tugged around and eventually jams up into the blinker cancel tab. I almost wonder if my hub is not seating all the way down onto the steering wheel splined shaft, which creates a small gap for the wire to work its way into the area where the cancel tab swings. So strange. I've put aftermarket racing wheels on other cars and never had such an issue lol!

That wire goes to a horn contact strip that screws to the top of the plastic housing. It does not go into your hub at all.

holy cow...that would explain it! I'll take a closer look tonight and report back. Thanks so much! This is such an aggravating problem!!!!

Well, john was right in identifying my screw up. I was thrown off because as you can see, my horn contact wiper switch is MIA (and the gold colored spade connector on my contact ring is completely broken off). Will order these parts. Thanks all!http://forums.pelicanparts.com/uploa...1525190140.jpg

Hi John, I’m really sorry to beat a dead horse with this topic. However, I could really use some help if you don’t mind. I understand all the steps to install a prototipo on my ‘86 Carrera, accept the horn button. From what I’ve studied, I’ll remove the oem wire from the back of the oem wheel, and run the wire into the momo hub and screw the oem wire harness in the back of the momo hub. What I’m confused by is the wire that came with the momo hub, I understand that this momo wire would act as a ground. And this momo wire would connect to the ground plate that you place at the top of the momo hub with the metal male connecting part(I don’t know what to call it, the momo wire would connect to it) but where do you affix the other end of the wire. I’ve read that someone drilled an extra hole in the ground plate and screwed the momo wire raw exposed wire end down through the added new drilled hole. Is this correct?

Tyvm

From what I've seen, the need of the additional ground wire depends on the type of horn button you're using. Theres horns with 1 attachment on the rear and theres horns with two. The one with two require you to running a ground cable between one of those two connectors and the Male connector on the 'ground plate'.

deleted. I see the original post was already resolved. with the same info I just posted.

Great info ty so much! My horn button has one attachment, perhaps the oem wire will fit and work? Really appreciate the info

Yes, that's correct. Feel free to post a pic of the rear of your horn. Pics usually tell a lot more.

Thx so much for the help! So here is an image of the back of my horn button, as mentioned it has one spade for the oem wire. Looking at the image you will notice a gold metal wire, if you follow this wire it continues to a hole, push the gold wire in and the wire in the hole opens a bit. I believe that the bare end of the momo wire that came with the momo hub gets pushed into this hole, releasing the gold wire will press the wire against the inside...if that makes sense, so now let’s call that the ground wire, as you attach the wheel the ground plate with the spade faces away from the driver and the momo wire whose bare end is now in that hole, fits on the spade of the grounding plate. Does this make sense at all? http://forums.pelicanparts.com/uploa...1564634809.jpg

I’m fairly certain that I swap out the oem wire crimp for the momo wire crimp that came with the hub, then the horn button will ground itself. If you know pls confirm, tyvm for the help!

Normally, your button doesnt require any additional wires. Only the original one that is there to operate the horn. That one should be fitted to the spade connector on the rear of your button.

The so called wired running out of the side on your button is your ground attachment. Those used to touch metal when being mounted inside old style hubs but the current ones (the collapsibles) have a larger center hole. So in order to make the wire from the horn touch ground, you may need to put one of these between your hub and steering wheel. (Sharp side mounted upwards)

P.S.: on the horn buttons with 2 spades, an additional ground cable is ran between the 2nd spade on the horn and the spade on this ring.

http://forums.pelicanparts.com/uploa...1564786757.jpg

Ty for the reply! Yes a grounding plate like the one you’ve shared was included in the momo hub kit. I plan to include it between the wheel and the spacer with the male tab facing away from the driver. That sound correct? I plan to try to first hook up the oem wire and assemble if the horn doesn’t work then I will cut the oem crimp off and attach the crimp from the momo wire that was included with the momo hub.

Ty so much I can’t wait to get it done! Sunday.

Hey man so I got the wheel on, the horn sometimes wants to work, I’m thinking that perhaps the paint on the wheel might be causing an issue. Not certain but for now I love the look! Ty for the direction!!
http://forums.pelicanparts.com/uploa...1564946379.jpg

No problem, you're welcome.

i don't see any paint on the wheel myself so i'm not sure if that's it. At least you know the wiring in itself is good, it's probably just one of the contacts that doesn't make good contact.

Hey man so I got the wheel on, the horn sometimes wants to work, I’m thinking that perhaps the paint on the wheel might be causing an issue. Not certain but for now I love the look! Ty for the direction!!