Headlights & Horns

[John Camp]

Hello,
I have a 1960 356B S90 with stock 6 volt electrics. I have developed several electrical problems that may or may not be related and wondered if anyone can provide some insight. The horn button on the car is currently missing. I have a new one on the way, so that will not be a problem soon, but in the meantime the horn contact randomly connects the circuit causing the horn to sound. To combat this issue I temporarily removed the horn fuse, but to my dismay, the horn still randomly beeps. Alongside this issue, my passenger side headlight only works on bright. I have tested the Bulb and it is not the problem. When testing the wires at the light plug, the voltage at the low beam wire is low and spotty. Additionally if I run a lead from the ground at plug to the ground on the headlight and from the 6 volt at the plug to the positive post on the headlight, when I make the connection the horn gives a short muted beep. Is there a relay that could cause these issues? My instinct is to replace the headlight relay with the bright light headlight relay kit available from Zim's, but not sure if I need to investigate in any other direction first. Many thanks in advance for any advice that you all can offer.
-John

[Mike Wilson]

#4 fuse powers the horn relay. When you honk the horn, you complete the ground. My guess is the steering column hub needs to be adjusted so it isn't in contact with the contact ring. Also make sure the horn cuff s pliant.

Joe Leoni's wiring diagrams are available on this website so you can tract down the electrical gremlins. I'd check the fuse block for the headlight issue. Low beam right side is fuse #9. See if you have power on either side when the headlight switch is pulled out.

Mike

[Hugo Karasawa]

The horn circuit is not protected by any fuse. #4 fuse protects the wiper circuit and the interior lights.
You may think that #4 fuse is for the horn circuit because the power cable for the horn relay is connected to the top of #4 fuse.
The headlight relay is a control device for the headlight flash, in this case nothing to do with brighter lights.

[Hugo Karasawa]

1.- Clean the contacts of the fuses at the fuse block.
2.-Check the wiring from the fuse block to the headlights. Remove fuse #9, apply 6V to the low contact of #9 at the fuse block, the headlight should light, if not the problem is at this part of the circuit.
3.-The low beams are powered by fuses #9 and #10 and these are powered from a common connection. At the fuse block this connector is at the back and one of the rivets that hold the fuse contacts can be loose.

To continue testing read the article by Greg Bryan "Headlight Circuit Troubleshooting" in the March /April 2015 Volume 38 number 6 Registry´s magazine. You can find it at the Media Center / Magazines

[Bill Oldham]

My guess is a corroded fuseblock. The rivets providing the top to bottom connection lose contact with the surfaces because of corrosion. You can verify this with voltmeter readings ( there should be only insignificant voltage drop across rivet connections). But the solution has been described by many: soldering the rivets to the metal surfaces they connect and it involves removal of fuse block, a lot of cleaning. And soldering. A PITA.

[Ken Tuvman]

What solved my intermittent horn working was replacing steering coupler- the wire on old coupler was corroded- not sure if that wire grounds other electric operations but it solved the horn issue. If it beeps when turning steering wheel Mike Wilson, post #2 is correct.
Good Luck!

[John Camp]

Hey Guys,

Thanks for all of the advice and suggestions. It ended up being an issue at the fuse block!

[Mike Wilson]

Mike