Headlights go on and off

[82sbshortbed]

Ok I've replaced the sealed beams with halogen bulbs. Cleaned up all the wiring under the hood. New running lights and front blinkers housing and sockets. It takes a while before it goes out the first time. Then like you see in the video. I've been told I need a new alternator. I put new battery in too. Maybe avnew headlights switch in the dash? Any help would be appreciated.

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[gmbellew]

does it do it if you give it some juice to up RPM? that may help determine if it is the alternator. does anything else cut out? does wiggling the switch do anything? did you add relays to the system? maybe the switch is getting hot and it is on its way out?

 

[squaredeal91]

Seems like grounds intermittently grounding. The rumble or the engine makes it do it maybe? Does it do it like in the video with engine off?

 

[squaredeal91]

On onother thought I've had weak relays come on and off like this once the relay heats up just like what I was seeing.

 

[Terry Wilkerson]

Could be hi/low beam switch.

 

[rusted nuts]

It looks like the circuit breaker is triping, New bulbs or something may be drawing to many Amps. Could also be bad ground. Put Your old bulbs back in, See what it does.

 

[SirRobyn0]

I'm thinking circuit breaker. It just seems to regular to be a switch or a ground issue.

 

[rusted nuts]

I just reread Your post, Did You replace all that stuff to find what is wrong or Because you wanted to update it? If You did it to find out what is wrong then I would be looking for a dead short Leave lights on and look for warm wires clear back to tail lights.

 

[gmbellew]

is there a circuit breaker on the headlights? I thought the only circuit breaker was for power windows?

 

[rusted nuts]

is there a circuit breaker on the headlights? I thought the only circuit breaker was for power windows?

I think there is, In a 73 at lease. Belive it is built in the headlight switch, You should be able to hear it click.

 

[Randy and Easton]

I agree with all above. grounds first, check alternator load and then headlight switch engine off. Then dimmer.

 

[gmbellew]

I think there is, In a 73 at lease. Belive it is built in the headlight switch, You should be able to hear it click.

you are right, integral to the switch it appears. it could be it is going bad or it is loading up with too much current from another issue in the wiring?

 

[WP29P4A]

I just reread Your post, Did You replace all that stuff to find what is wrong or Because you wanted to update it? If You did it to find out what is wrong then I would be looking for a dead short Leave lights on and look for warm wires clear back to tail lights.

In 46 years of trouble shooting low volage electrical problems, I have never seen a dead short that didn't either blow fuses, melt the fusible link, or burn wires. Dead shorts are the easiest to locate due to the trail of destruction they leave behind. The high resistance shorts are the hard ones to locate.

 

[gweed]

I had the exact same issue. I have an 84 K5. Bought and installed the LMC truck kit. I also replaced the headlight switch, put the new halogen lights in and when running high beams my lights would flicker on and off and go out completely until I turned off the high beams. Its the thermal fuse in the headlight switch. The newer lights draw more amps. Your options are to put relays in for your lights so that your light switch does not draw too much current, or replace your high beams with LEDs as they draw less current. I kept my low beams halogen so that they will melt the snow and ice and put LED bulbs in the high beam lenses. Problem solved for me. I run a pretty stock alternator, have upgaded the big 3 wires and have a new battery. Battery, grounds and alternator had nothing to do with my issue. The headlight switch was the weak point in my system.

Shawn

 

[82sbshortbed]

It's done that since the day I bought it. Drove it home at night and got lucky I didn't get stopped. Had some friends that followed me. The battery wires were lose and thought that was it. But no. The po switched out front clip and added the suburban grill and lights. So I replaced the sealed beams with new ones and cleaned grounds. Still did it. Replaced the sealed beams with these from lmc. Cleaned up the shotty wire connections and added two new running light sockets too. Added a relay to have all four come on when I put them on Brite lights. Now it takes longer until they blink on and off. Then they do it consistently.

Also the po has put in a tilt colum with the hight beam switch on the blinker switch that you pull back on. There's a bunch of wires under there that I don't know what they go to. So that could be causing me trouble. My dome light doesn't work either. No dash lights. I'm not the best at wiring but better than the po. Lol

Buddy at work suggested alt. It checks 14.4v at battery running lights on. How do I check the amps it draws? I'm kinda thinking the light switch. But that's a guess because I've replaced all the lights and cleaned up the wires under the hood.