hot, smoking headlight switch

[Guest]

Ok guys, I've tracked down my under dash smoke and found my headlight switch is getting hot and smoking.
Is it just best to replace or can it be repaired.
Cheers Chris.

[jopizz]

There are instructions in the Technical Resource Library on how to take it apart and repair it. It's not difficult so I would try that first. I've found that the quality of some of the replacement switches is rather poor. I would rather repair original parts if I can.

John

[Yadkin]

Try cleaning it as suggested. Then install relays for your headlights under the hood. Supply the relays with 15 amp fused circuits directly from the battery. Then your dash and floor switches will be low amperage.

[scumdog]

Try cleaning it as suggested. Then install relays for your headlights under the hood. Supply the relays with 15 amp fused circuits directly from the battery. Then your dash and floor switches will be low amperage.

Exactly what I did.
And mounted the double relay behind the windscreen washer 'bag' , I ran a 'hot' wire from the starter relay across the top radiator support to the drivers side of the car to a post type terminal that I source power from for my headlights and horn. (Which is also run off another relay)

[Guest]

Thanks, I like the idea of the relays.
Would anyone have a small wiring diagram of how that works and would be setup.
Thanks Chris.

[simplyconnected]

Chris, I made what we call a 'ladder diagram' for you. I think it is easier to understand than an 'elementary diagram' or a 'wiring diagram'.

Fuse sizes are matched to the wires and relays. In other words, if you buy a relay with contact ratings for ten amps then you would size the fuses or circuit breakers to 8-amps (or so).

If you have questions, please ask. BTW, you can get relays and pre-wired sockets from eBay for under five bucks each.

[Guest]

Excellent Dave, thanks.
Hopefully I've got this correct.
From the battery I run a cable to pin 30 on the relays.
The dash side of cut wires will be connected to pin 86 and fused accordingly. If I run 20 amp relays I'll install 15 amp fuses.
If I use 5 pin relays both cut headlight wires will each go to pin 87. Low beam red/black and high beam green and black.
And 85 is grounded.
Does this sound correct.
Obviously I'll either need to replace or repair the original switch or will the relays be enough to take off the load.
Cheers Chris.

[simplyconnected]

Let me label some of these relay elements for you on the ladder diagram.

The coils are not fused but the contacts are. Either of the relay coil wires (85 & 86) can be connected to neg., and either of the normally open contacts (30 & 87) can be connected to the lamp. Simply put, they are not polarity sensitive.

As per the diagram, run a +12 wire into a fuse which feeds a normally open contact, that controls one filament of the sealed beam. The diagram is duplicated for the second filament. More sealed beams are paralleled with the ones shown in the diagram.

I would open your headlight switch and look, to determine whether the switch needs to be changed. Relays will lighten the load by a lot.

[Guest]

Thanks Dave, much clearer.
I'll open the switch and have a look.
It's very oily/greasy on the outside which hopefully is just due to excessive heat.
I'll give it a good clean on the outside install relays and go from there.
Cheers Chris.

[Yadkin]

Thanks Dave, much clearer.
I'll open the switch and have a look.
It's very oily/greasy on the outside which hopefully is just due to excessive heat.

Sounds like someone "cleaned" it with WD 40. Don't be that guy.

You can buy contact cleaner at your local big box home improvement, or better yet local hardware store, in the electrical department. Use that with an old toothbrush and scrubba-dubba.

That reminds me, did you know that the toothbrush was invented in West Virginia? Otherwise it would be called a teeth brush.

[Guest]

Yeah it does seem someone has cleaned it with something like wd40, definitely wasn't me. I'll get some contact cleaner an do that.
Haha so I take it the west Virginians are like our version of tasmanians.

[Yadkin]

Yes, if Tasmanians are the butt of all great jokes.

What is the West Virginia state flower? The Satellite dish.

By the way I tried cleaning mine about a year ago; the variable resistor wires were broken in several places, so I ended up buying a reproduction. Since I have a '64 model I can use a lot of Mustang parts, which can be of higher quality as they are available from many suppliers. The '64.5 Mustang switch is shorter, so I had to cut down and dremel a point into the plunger of my dash knob.

[simplyconnected]

http://squarebirds.org/images_headlight_switch/

In case you didn't see my write-up. - Dave

[Guest]

Yep I did Dave, actually read through it twice last night.
Cheers Chris.

[Guest]

Just a quick question, is it ok to take 12v off the alternator or does it need to be a constant 12v direct from the battery and secondly what would be the ideal amp rating for all associated wiring.
Only reason I ask is majority of my wiring is either hidden or rerouted away from standard.
Thanks Chris.