Headlights go out on random.

[NUTNDUN]

Hey gang,
I am still ironing out some little bugs here and there after getting the truck back on the road. Today was the first day I ran it in the dark for an extended period (over 10 minutes) All of my lights work as they should and I just had it inspected. I got about 15 minutes from the house this morning and the headlights went out, only the headlights all other lights stayed on. I was getting ready to pull off the side of the road and I pushed the switch in and pulled it back out and they came back on. I kept going, not even 1 more minute it did it again and again so I pulled over and turned the lights out. I sat there for maybe 3 minutes and turned the lights back on and went on up the highway, it was fine for 5 of the 7 mile and it started doing it again, except this time they would go out and come back on their own. I pulled off again and sat there for about a minute with the switch off, turned it back on and continued my last 2 mile in to work.

I don't know if it is a bad ground or if maybe the switch is going bad or if it is getting too hot. The only thing I have done electrical wise is added the reverse lights to the circuit with my hurst shifter and added a powermaster one wire 140 amp alt.

[ezernut9mm]

souds like your switch is toast. they get hot ad short themselves out.

[fitzwell]

one of the members here makes an upgrade kit that uses relays (triggered off the existing headlight wires) to deliver power to the headlamps. Wise investment, IMHO

[fordman]

the headlight switch has a circut breaker in it. so when it gets hot it shuts the lights off. and canmake your lights blink when it gets to the right spot of hot and cool. back and forth.

[NUTNDUN]

I appreciate the input. I ordered a switch and it will be in tomorrow. I will definitely want to check out the relay that a fellow member makes. Is it because the circuit breaker gets weak over time? I didn't have a problem with it when the truck was together three years ago. It also probably didn't have as much voltage available either now that I have that 140 amp alt on her.

[kaptnkaos]

Hey NUTNDUN,

I, for one, can't say enough good stuff about Paul's (390nut) upgraded light harness'.
I have gotten 3 from from him. I put one in my '68 bus "Olde Skool", one in my '68 CS and one in my brother's '72 CS.. remarkable difference.
If you have upgraded your headlights from the stock ones, they draw more power which causes the breaker in the switch to heat up faster and trips the breaker.
Something else that will make your lights blink on and off is a bad dimmer switch. The connections can get loose or corroded and cause problems.

KaptnKA S

[NUTNDUN]

When you say dimmer do you mean the high beam switch or the dimmer in the headlight switch for the interior lights and dash lights?

[kaptnkaos]

The floor switch... it can get corroded pretty bad and the connections can loose conductivity...

[NUTNDUN]

Then the dimmer may be my problem. I know it is a little loose on it's mounting. I will have to check the wiring on it or maybe kick it when it does it again and see if that changes anything. I still think it will be a wise ides to replace the switch anyway and I would like to get the headlight relay too because I do have aftermarket headlights in the truck.

[Lar4t9r]

Then the dimmer may be my problem. I know it is a little loose on it's mounting. I will have to check the wiring on it or maybe kick it when it does it again and see if that changes anything. I still think it will be a wise ides to replace the switch anyway and I would like to get the headlight relay too because I do have aftermarket headlights in the truck.

When I first got my '69 bump, I had the intermittant headlight problem and an old freind of mine told me to check the dimmer switch on the floor first. It looked fairly new and all connections looked good, but cleaned them up anyway. Tried again, had the same problem. Then got my test light out and checked, seemed to be fine. Then with motor running and headlights on, waited until the headlights cut off and checked again. Sure enough it was a bad dimmer switch. Picked a new one up at NPD, have not had a problem since.

[NUTNDUN]

I have a feeling it is the main headlight switch. I went to take the truck tonight and the headlights came on but no parking lights and no interior lights, pushed the switch in and all the way out and same thing. Got it backed out and messed with the switch again and the parking lights came on. Went on down the road and all was fine and then the headlights started turning of, mess with the switch and they come back on. The ride home they didn't act up at all.

[kaptnkaos]

Yeah NUTNDUN,

That does sound more like the light switch...
You might also want to check and clean all of the grounds.
A good percentage of light problems on our trucks are caused from poor grounds.
You should be able to pick up a new light switch for around $20 at just about any part house...
I think the dimmer switch was around $10.
I replaced both on my '68 CS...
I have systematically replaced almost every switch on the truck.
The only one I have had problem with is my turn signal switch.
I replaced it with a new one from NPD and have had nothing but trouble with it...

KaptnKA S

[NUTNDUN]

You know it is funny you mention the turn signal switch. I don't know what happened in the three years the truck sat in pieces but when you turn the wheel to the left it clicks every time the wheel comes around. The turn signals work fine though LOL.

[NUTNDUN]

I figured I would post an update. New headlight switch did the trick. Now I have other problems and the motor may be coming back out for a tear down. Unless it is a fluke chance that the roller rockers coming a little loose attributed to not running as good and a stone got kicked up into the flywheel causing a screeching sound. I don't have the dust shield on the bellhousing (I know stupid me and didn't think about it when I put the tranny up in. I guess this will all be for another thread.