Hi FTE, I am having a problem with my 73's lights. I was driving the truck all day in the rain today, no issues whatsoever. Just as I went to park, the lights began flickering and there was an audible clicking coming from the headlight switch area that was clicking at the same rate as the dimming and flickering of the lights. My parking lights and taillights refuse to work, but I have brake lights just fine. I have a video I will try to post here. Thank you in advance!

 

 

I do not need a video to know it sounds like your headlight switch is about shot. Or you have some sudden connection problem, any smoke or burnt smell from the dash?

Ck fuses, elec connections, anything wiring wise get against the exhaust manifold?

Ok I watched the video anyway...lol wow that is odd.

 

Thank you very much for your reply.

I would really be happy if it was just the switch! The connections seem fine and I see no shorts, though I replaced the back up light fuse with no change. It did this once before and then subsided. Still sound like the switch to you? I can see the parking lights just barely give an attempt to turn on when the lights blink. No amount of wiggling, jiggling or fidgeting of the switch will make the lights do anything different.

 

Since is did it while you were not touching the headlight switch I would suspect a wiring, alternator or some sort of power issue?

 

Would too little power cause this flickering issue? I noticed that the switch was pretty warm after driving a while, could that have something to do with it?

 

First thing I would check is voltage regulator.

 

A hot headlight switch sounds like something is wrong for sure. Might be time for a new headlight switch or a LMC Heavy-Duty Harness?

Truck Parts and Truck Accessories

X2 on maybe the VR?

 

A new headlight switch looks like a plan. If I just turn on the parking lights they still just barely try to turn on, and the taillights make no attempt whatsoever.

 

I am going to let the truck sit a while and see if it was just a wet wire or something.

For now, my temporary solution:

 

beating a dead horse maybe - check your light grounds too. Bad grounds cause all kinds of weird symptoms, and that it happened in the rain kinda supports that theory

 

Thank you for the reply! Certainly not beating a dead horse, since I haven't fixed it yet. Where are the light grounds located?

 

Doesn't the switch have a built in circuit breaker for the headlights only?? Seems to me I remember this. If so it sounds like you have a short in the headlight circuit somewhere and its tripping and resetting. Might want to have a look at the dimmer switch too pull it up and look at the connections. They are susceptible to mud/moisture shorting them out due to their location.

 

Those headlight switches weren't made to carry that much juice - that's why you hear about a lot of headlight relay changeovers. Check the white (I believe) wire on the switch - with lights, etc, on....could be getting a wee bit overloaded/warm, etc..

Agree on changing/checking the switch.

Let me help whip that dead donkey......can't have too many grounds.....in the back, for the rear lights should be two grounds of the same nature. Check yer pigtails fer corrosion, ground continuity.

on the left and right side of the core support, under the flappy gizmo are headlight grounds

 

Came here to say this. Headlight switches have a self resetting circuit breaker that uses heat to trip. It might be possible that once it's trip, it'll keep cycling on/off like this.

Seen it once on a buddies van where we wired up extra lighting, and another buddy was vehemently against relays and the lights kept wigging out like this.

Either replace headlight switch or use a headlight relay kit (especially if using high power lights). After checking for obvious damage to wiring and grounds like the others have said.