Hello! Log in or Register   |  Help  |  Donate  |  Buy Shirts See all banner ads | Advertise on TheSamba.com  
TheSamba.com
 
No horn in reverse
Forum Index -> Vanagon Share: Facebook Twitter
Reply to topic
Print View
Quick sort: Show newest posts on top | Show oldest posts on top View previous topic :: View next topic  
Author Message
sphet
Samba Member


Joined: November 09, 2016
Posts: 345
Location: Vancouver, BC
sphet is offline 

PostPosted: Wed May 26, 2021 7:52 pm    Post subject: No horn in reverse Reply with quote

I was at the lumber yard last weekend and double-honked when backing up but nothing happened. At first I thought it was something with the horn or the steering wheel switch, but putting it back in neutral and the horn worked fine. In reverse again and no horn.

Does anyone have any insight on why I might have no horn in reverse? I have a 4 speed manual with push-down reverse gear.
_________________
1982 Diesel Westfalia 1.6 NA - The Shellakabuukiee
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Vanagon Nut
Samba Member


Joined: February 08, 2008
Posts: 10362
Location: Sunshine Coast B.C.
Vanagon Nut is offline 

PostPosted: Wed May 26, 2021 8:24 pm    Post subject: Re: No horn in reverse Reply with quote

Long shot theory:

horn circuit grounds are so dirty and corroded, that added load of reverse lights pulls power down so that remaining power can't over come the dirt and corrosion on horn ground circuit?

See if horn works while reverse is engaged but all other loads are off?

On the '82 diesel, the horn and reverse lights appear to be on the same fuse. But, I can't see a fault in the reverse light circuit affecting the horn circuit per se. e.g. a short to ground on the reverse light circuit should cause the fuse to blow.

Neil.
_________________
1981 Westy DIY 15 ABA

1988 West DIY 50 ABA

VE7TBN
Back to top
View user's profile Send private message Gallery Classifieds Feedback
sphet
Samba Member


Joined: November 09, 2016
Posts: 345
Location: Vancouver, BC
sphet is offline 

PostPosted: Wed May 26, 2021 8:28 pm    Post subject: Re: No horn in reverse Reply with quote

Vanagon Nut wrote:
Long shot theory:

horn circuit grounds are so dirty and corroded, that added load of reverse lights pulls power down so that remaining power can't over come the dirt and corrosion on horn ground circuit?

See if horn works while reverse is engaged but all other loads are off?

Neil.


Neil,

Thanks for this idea. I was looking over the Bentley wiring and it doesn't seem like there could be too much magic, but this might be the case. I will try this weekend pulling the reverse bulbs from the tail lights and seeing if the horn works any better.

S
_________________
1982 Diesel Westfalia 1.6 NA - The Shellakabuukiee
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Vanagon Nut
Samba Member


Joined: February 08, 2008
Posts: 10362
Location: Sunshine Coast B.C.
Vanagon Nut is offline 

PostPosted: Wed May 26, 2021 8:36 pm    Post subject: Re: No horn in reverse Reply with quote

You're welcome.

Two other thoughts:

fuse contacts are dirty and-or the fuse isn't making the best contact. Added load of reverse lights creates a similar issue.

Another long shot theory and highly unlikely: as you put bus in reverse, steering wheel position changed slightly which caused a section of the brass ring at wheel to make poor contact.

Neil.
_________________
1981 Westy DIY 15 ABA

1988 West DIY 50 ABA

VE7TBN
Back to top
View user's profile Send private message Gallery Classifieds Feedback
jimf909 Premium Member
Samba Member


Joined: April 03, 2014
Posts: 7450
Location: WA/ID
jimf909 is offline 

PostPosted: Wed May 26, 2021 9:02 pm    Post subject: Re: No horn in reverse Reply with quote

A relay at the horn will provide a short, direct, reliable path to ground. Running a positive direct from the battery will allow for heavier loads and louder horns. I use the Stebel Nautilus.

A good thread on the relay here. Go to the second or third page for the wiring diagram.

crazyvwvanman wrote:
You need a relay. Also, YOU NEED A relay!!!!

The problem isn't the power feed to the horn. The weak spot is the ground wire path to the horn button. That path is weak and gets weaker with age. The relay gives that path a much easier load to carry.

Mark


Louder and hornier...
https://www.thesamba.com/vw/forum/viewtopic.php?t=...mp;start=0
_________________
- Jim

Abscate wrote:
Do not get killed, do not kill others.


Current: 1990 Westy Camper - Bostig RG4, 2wd, manual trans w/Peloquin, NAHT high-top, 280 ah LFP battery, 160 watts solar, Flash Silver, seam rust, bondo, etc., etc.

Past: 1985 Westy Camper - 1.9 wbx, 2wd, manual trans, Merian Brown, (sold after 17 years to Northwesty who converted it to a Syncro).
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Abscate
Samba Member


Joined: October 05, 2014
Posts: 22629
Location: NYC/Upstate/ROW
Abscate is offline 

PostPosted: Wed May 26, 2021 11:59 pm    Post subject: Re: No horn in reverse Reply with quote

The voltage pull down theory makes sense. Test as above.

Simpler test, go into reverse, push down horn butyon, pop out of reverse and see if horn starts.
_________________
.ssS!
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Ronzo_volvo_guy
Samba Member


Joined: December 31, 2015
Posts: 194
Location: Connecticut
Ronzo_volvo_guy is offline 

PostPosted: Thu May 27, 2021 4:56 am    Post subject: Re: No horn in reverse Reply with quote

sphet;

I agree with Niel (Vanagon Nut) and his explanation totally...interaction of two normally unrelated circuits is often (almost inevitably!) caused by them being connected to the same grounding point, and that point then developing an in-line resistance, which results in the two circuits becoming functionally related (and making for some highly wacky symptoms as you have noticed!...no, your vehicle is not possessed!). See also: https://www.sw-em.com/electical_circuit_interaction.htm#Chassis_Side_Inadvertent_Circuit_Interaction

...but it CAN also occur when two unrelated circuits have the same power source (like being on the same fuse), see interaction of Headlights and Tach in a sport Volvo at link (you Vanagon Owners are not the only one blessed with wacky symptoms!).

Try to locate the point where these two circuits share this ground/chassis connection (refer to your Bentley!), and while the symptom is occurring (in other words, while drawing current, because ONLY while drawing current does the voltage develop, and allow/cause symptoms), and measure the voltage on this point (probably the "star ground"as this seems to be common place of issue on these vehicles)...if you measure something other than 0V, you have found the precise spot to direct your attentions...clean to shiny metal, lather up with ACZP (See: https://www.sw-em.com/anti_corrosive_paste.htm ) and reconnect...obviously, once you're there cleaning connections, you should clean and treat all other connection in sight (and checking the push-on spades for snugness while you're there can't hurt!), but after this (repair and preventative) action, you might just find that the function of some other circuits will improve also (they were being affected by that voltage also!)...

Cheers from the vintage Volvo world, and Good Hunting!

Edit; In looking around, I found this excerpt, from what looks like the Bentley manual, where it is clear that the Backing Light and Horn circuits are very close...even sharing the same S10 fuse...if I study this a bit further, I might even be able to suggest where the dreaded in-line R is occurring (I love a theorectical electrical failure analysis challenge...I'm not even seeking help about it!) http://www.haywood-sullivan.com/vanagon/dual_horns_wiring_diagram.gif ...please let us know your findings/corrections so that everyone can learn from them!
Back to top
View user's profile Send private message Classifieds Feedback
Ronzo_volvo_guy
Samba Member


Joined: December 31, 2015
Posts: 194
Location: Connecticut
Ronzo_volvo_guy is offline 

PostPosted: Thu May 27, 2021 6:37 am    Post subject: Re: No horn in reverse Reply with quote

sp;

...a couple of questions to help troubleshoot...maybe you can engage a helper to answer the following:

1. With Ign ON, and in Reverse, can you hear the Horn Relay click, when the horns themselves are silent.

2. With Ign ON, and in Reverse, are the Reverse Lights actually ON? Does anything about them change (like brightness, or the fact that they go ON or OFF) when you then try the Horn Button?

Good Hunting!
Back to top
View user's profile Send private message Classifieds Feedback
MarkWard
Samba Member


Joined: February 09, 2005
Posts: 17099
Location: Retired South Florida
MarkWard is offline 

PostPosted: Thu May 27, 2021 7:40 am    Post subject: Re: No horn in reverse Reply with quote

Stock, no horn relay. They get power and the button completes the ground I believe. As mentioned, they share the same power supply. Key on. 15. The backup light also completes a ground. So, I like Neil's suggestion that there is a voltage drop across the fuse.
_________________
☮️
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Ronzo_volvo_guy
Samba Member


Joined: December 31, 2015
Posts: 194
Location: Connecticut
Ronzo_volvo_guy is offline 

PostPosted: Thu May 27, 2021 7:51 am    Post subject: Re: No horn in reverse Reply with quote

Mark; What about that linked "typical" Wiring Diagram ( http://www.haywood-sullivan.com/vanagon/dual_horns_wiring_diagram.gif )...it clearly shows a Horn Relay...? ...or is that the difference between single and dual horns?

Sp; Can you confirm which configuration you have...with dual with Relay or single with none?

Cheers

Edit; Can you or Mark maybe post the applicable wiring diagram for no relay config, if that what you have...
Back to top
View user's profile Send private message Classifieds Feedback
MarkWard
Samba Member


Joined: February 09, 2005
Posts: 17099
Location: Retired South Florida
MarkWard is offline 

PostPosted: Thu May 27, 2021 8:56 am    Post subject: Re: No horn in reverse Reply with quote

Can't really post a diagram from the factory manual, but for those interested. I'm looking at page 97.37 in the manual for 82 diesel. Shows fuse 12, 8amp powers both horn and backup light. The manual is not 100% correct, but there is enough information to troubleshoot most circuits. The ceramic fuses tend to get corrosion especially if the windshield is not sealed completely. There are also some cheap copies of ceramic fuses. Power is direct from the ignition switch for that circuit, so that could be another possibility, but less likely.
_________________
☮️
Back to top
View user's profile Send private message Gallery Classifieds Feedback
sphet
Samba Member


Joined: November 09, 2016
Posts: 345
Location: Vancouver, BC
sphet is offline 

PostPosted: Sun May 30, 2021 10:15 am    Post subject: Re: No horn in reverse Reply with quote

Thanks Mark,

I did follow the Bentley wiring and, as you say, the backup lights share the same circuit. I do have some moisture from my windshield so I will look at the fuses.


Today I confirmed once again that it is gremlins:

In neutral the horn works.

In drive it works.

With the food breaks on it works.

In reverse it worked! Then it didn't.

Back in neutral it works.

In all cases it is a bit anemic but it's always sounded like that.

We're heading out camping for a couple of days I will get back to it on my return.

Thanks for the help.

s
_________________
1982 Diesel Westfalia 1.6 NA - The Shellakabuukiee
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Abscate
Samba Member


Joined: October 05, 2014
Posts: 22629
Location: NYC/Upstate/ROW
Abscate is offline 

PostPosted: Sun May 30, 2021 10:28 am    Post subject: Re: No horn in reverse Reply with quote

Excessive current draw in reverse light circuit or horn

Diagnostic. Monitor voltage on reverse lights during operation
_________________
.ssS!
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Display posts from previous:   
Reply to topic    Forum Index -> Vanagon All times are Mountain Standard Time/Pacific Daylight Savings Time
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

About | Help! | Advertise | Donate | Premium Membership | Privacy/Terms of Use | Contact Us | Site Map
Copyright © 1996-2023, Everett Barnes. All Rights Reserved.
Not affiliated with or sponsored by Volkswagen of America | Forum powered by phpBB
Links to eBay or other vendor sites may be affiliate links where the site receives compensation.