The Stovebolt Site Forums The Shop Area The Electrical Bay Headlights went out

A few weeks ago,on the way home from some friends, after a nice dinner, the headlights went out on my '55 2nd.`(fun stuff, no street lights.) They worked OK for a while, then last week did it again. I pushed the dimmer switch, and they came back on again. I got a new switch from LMC, and when installing it noticed the spade connectors were loose and corroded. Lights work good now, but thinking a good cleaning and titening of the spade connectors would have fixed the problem?

The headlight switch has a thermal circuit breaker. It resets itself after cooling. So it may have been that rather than the dimmer switch. The extra resistance of the dirty terminals could have caused the breaker to trip.

yes a good cleaning of the connectors and tightening or replacing them is always a good thing to do.if you have corrosion going back up inside the wire, cut it back to clean wire and splice in a new piece of wire.

As resistance goes up, as in the case of dirty contacts, current goes down. As circuit breakers are current sensitive, I don't think that problem would trip a breaker. On the other hand, your light output would suffer and your chances of a fire go up. So, low resistance connection are indeed necessary.
As always, installing a current relay is a good idea. It takes the high current loads off old parts like headlight switches and dimmers. Bad connection problems can be minimized as the operated at around 50ma (0.050 amp).

ON my modified 54 I have aftermarket dimmers on the tilt wheel lever. Mine go out from time to time the first time when I was 600 miles from home. I put the high beams on and left them on all the way home. Maybe it is a thermal overload because it is intermittent.

I'm a little obsessive about lights, steering, and brakes. The very best is just barely good enough when I'm betting my life of those systems working. I'd suggest installing a new headlight switch, a new dimmer switch, AND setting up the headlights to work off relays rather than running full current through two switches in series with each other. An added advantage will be brighter headlights, especially on a 6V system. A 60 amp capacity Bosch-type relay can be wired to default to low beams by flipping a simple toggle switch in case there's ever a failure of the main headlight switch/dimmer system. Sort of a belt and suspenders situation!
Jerry

I am not familiar with the headlight switch on a Task Force truck, but the Art Deco and Advance Design switches have a bi-metallic circuit breaker in them. On my '42 I have experienced sudden loss of headlights on a dark road. You also get loss of the dash lights at the same time, which would not happen if the problem is with the dimmer switch.

Beltfed, Cletis is correct and what happens is dirty contacts lead to resistance, which leads to heat, (as well as current loss as you point out) which opens up the bi-metallic contact points.

Kent

the TF trucks have the same circuit breaker in the headlight switch. This is designed to allow a reset after the overload situation is resolved so the headlights will be restored.

Actually high resistance does not lead to open bimetallic contact points. Over current through the bimetallic strip, which occurs due to low resistance such as a short circuit or too many loads, does that. Dirty contacts, bad grounds, corrosion, etc., won't blow a fuse or trip a breaker. A high voltage drop occurs in these cases which naturally limits current and results in dim or no lights in a lamp circuit or no operation at all on other systems.

Foot-operated dimmer switches live in a very hostile environment due to rain, road dirt and salt getting splashed onto them continuously and they are prone to develop open circuits- - - - -no lights- - - -and shorts- - - -circuit breaker trips- - - -no lights. Either way, you're flying blind until you tap the switch and hopefully clear the open or short. Regardless of the cause, you're still likely to be just as dead either way if you happen to be on a dangerous stretch of road.

"Here lies the body of Solomon Gray- - - - -
Who died while defending his right of way- - - -
He was right, dead right, as he sped along- - - -
But he's just as dead as if he were wrong!"

Getting hung up on semantics doesn't seem to be very helpful here.
Jerry

Tomctomc,
OK let me try this again; above I was referring to a normal load (such as head lights, tail lights and dash lights) all which go through the headlight switch bimetallic breaker. The breaker switch has points just like the points in a distributor. If the contact surface is dirty and corroded the current is reduced due to the resistance and heat is produced (just like a resistor or light bulb). Since the construction of the points is bimetallic, the points separate, causing all of the lights to go out. I am not talking about dirty contacts elsewhere in the circuit, which I agree with you; just the breaker itself.

I understand the breaker is designed to heat up only when there is too much current through the points, which also causes it to heat up and open, but correct function requires a good contact between the point surfaces. I experienced this phenomenon one time and was burned by the hot breaker when I reached under the dash in an attempt to find out why I suddenly lost lights. My switch was aftermarket which had a replaceable breaker which allowed me to fix the problem by replacing only that element of the switch.

Kent

Can you link me to a headlight switch with a replaceable breaker?
The only replaceable part I've seen is the 4 Amp glass fuse that just protects the dash lights/dome light.

Bartamos,
I think Jim Carter's universal 12volt switch has the thermal circuit breaker,located at the very rear of the switch mechanism,

http://www.oldchevytrucks.com/cart/product.asp?prodid=EL160&i=9764|||||

The breaker is held to the mechanism by the two bolts/leads you see at the very rear. I don't remember where I got the new circuit breaker itself, possibly from an electrical parts place,
Kent

bartamos,
I was looking at the Jim carter switch that Lightholder's Dad posted and could not see a replaceable circuit breaker.
Then I saw this Switch and realized that the box on the back of the switch is the circuit breaker.
If you look at the Jim carter switch that same box is on the back of the his switch.
It is just turned 90 degrees and it is kind of covered buy the circuit board.
There are two electrical connecting post on the circuit breaker, one connects to
the switch's bus bar and the other post accepts the vehicle's battery power.

I Googled Automotive Auto-Reset Circuit breaker there are quite a few to choose from.

Here is another Switch that shows the circuit breaker better.

I had the headlights go out on my '53 one night about midnight. No dash lights, nothing. I hit the dimmer switch but that didn't change anything. Then my lights worked fine for a week and a half and then happen again. So I started doing some tests.
I would hook up test leads turn the lights on, everything worked fine, turn them back off. Hook up a different test, turn the lights on, everything works fine, turn them back off. Over and over again, same thing. Then one time I pulled the light switch out and there was nothing, no power from the switch.
I pulled three old light switches out of a box of spare parts I had and found that two of them had bad headlight terminals. One was loose and the other one was entirely missing. It looked like it had been burned out of the switch. When I pulled the original switch out of my truck I found a loose headlight terminal.
I think as soon as the weather warms up I'm going to wire in some relays to prevent all that current running through a sixty-year-old headlight terminal.