Head Light Issue

[dtbnz]

Hi All,
I have a 1982 K19 Silverado, that was imported into New Zealand from California.
Problem I have is that when I put the headlights on full beam, after about 5 minutes they start flashing and all headlights will go out. If I press the dip switch the low beam comes on OK, and low beam stays on all the time, but full beam keeps going out for some reason.
I have replaced the dip switch, and light switch, and still the same.

When I got it, (for the road compliance), I had to change the full beam headlights so that they focus on the left side of the road (we drive on the left hand side). I do not know if this has anything to do with it as it was a straight swop and do not know if this issue has always been with the truck?

Any ideas guys, your help would be appreciated.

 

[MikeB]

If the high beams on both sides do this, it could be caused by a poor connection between engine compartment lighting harness and firewall connectors. Although the connectors are greased at the factory, it wouldn't be unusual to find some corrosion there.

High beam is the light green wire near the bottom of the center plug-in connector. Loosen the bolt and pull out the entire center connector housing. If the connectors are corroded, they can be cleaned using a burnishing tool or a soft wire brush.

My 82 C10 firewall connector. The lighting harness plugs into the middle.

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[MikeB]

The problem could also be a corroded connector terminal on one of the wires connected to the "dip" switch.

Also check the high beam connections at the headlights.

 

[chengny]

The fact that the headlights flash on and off - when on high beams - would indicate that the current flow in the headlight circuit is excessive.

The power for the H/L's is straight from the battery - it doesn't pass through the fuse block. Over-current protection for the H/L circuitry is provided by a self-resetting circuit breaker - which is located inside the body of the headlight switch.

It will trip and reset itself repeatedly when the load exceeds 16.5 amps. But after a while, the breaker just gets too hot to reset itself and the lights must be turned off until it cools down.

I won't attempt to tell you what is causing the excessive current flow - it could be as simple as having over-wattage sealed beams installed.

But, if you are sure the lamps are correctly sized and the front lighting harness has not been modified - still appears to be stock - I would do as MikeB suggests. Check all the connections/splices throughout the circuit. Make sure they are tight and free of oxidation. Also inspect the wiring insulation - especially in those sections that are not protected by the plastic loom. Look for chafing and pinch points. Chafing can cause a short circuit to ground and a pinch point will cause excessive resistance - which increases amperage.

I might be way off on this - it could just be an intermittent wiring connection. You should really find some way to measure the current draw in the yellow wire between the HL switch and the dip switch. If it exceeds 16.5 when the highs are selected, that would seem to confirm my theory that it is the internal circuit breaker that is (appropriately) causing this to happen.

 

[MikeB]

Over-current protection for the H/L circuitry is provided by a self-resetting circuit breaker - which is located inside the body of the headlight switch.

It will trip and reset itself repeatedly when the load exceeds 16.5 amps. But after a while, the breaker just gets too hot to reset itself and the lights must be turned off until it cools down.

I learn something new every day. I didn't realize the thermal breaker would reset itself so quickly. But what you're saying makes sense. An intermittent or high resistance short to ground may be the problem, especially if some previous owner ran something like 100 watt high beams that melted the wire insulation.

I'd disconnect the high beam wire from the hi/low switch and headlamps, and then measure resistance to ground. Then again, the short could be to another wire in the bundle with melted insulation caused by too much current in the neighboring high beam wire.

Funny story: Had a friend put high wattage brake light bulbs in his old Jeep Cherokee. Worked great around town, but when he went exploring off-road, he had to ride the brakes down a long steep trial. The bulbs got so hot they melted the lamp housings and fell out the back to hang by their wires below the bumper! He said he drove a couple hours on the highway before he noticed the problem at a gas station.

 

[dtbnz]

Thanks Guys, will try all your suggestions and get back to you, hopefully with the good result. I'll also check the wattage of the sealed beams as well, in case they have something to do with the problem.

 

[dtbnz]

Spent a few hours today check my headlights.
Started off as suggested by MikeB,

Put a meter between wires in dip switch and got:-
With engine idling
Low beam = 7 Amps
High beams = 14 Amps
Dont know if this is good or bad?

Checked and cleaned all connectors, earth wires etc.
Found some chaffed and open wires under the battery box going to the headlights, so cut out the bad bits, extended, soldered and covered with shrink tube.

Checked Amps again and they had both dropped 1.0 Amp.
Ran lights on full beam and waited.
Usually after 5 mins they will start flashing and as Chengny very well explained, the circuit breaker in the switch will operate and eventually turn lights off.

After 15mins nothing happened so thought I may have fixed, however at 20mins they started flashing again.

Noticed the dip switch was getting warm, replaced with original, that too got warm, so put this down to Amperage draw?
Also disconnected each hi beam one at a time, and checked Amps, which dropped same amount.

Then checked headlight to see if their wattage had anything to do with it.
It still has I think the original high beams in the two bottom locations which are Wagner H4651 50watt. These are Halogen, does that sound correct?
The new Hi/Low beams are Revolution (Aussie made) Part No. 62-99962 which are also Halogen 65/55 Watts.
Still have the original Hi/Low beams which are Sylvania H4656 35/35 Watts.

Have original wire loom, so should the 65/55 halogens work or are they to high for the wiring loom?

One good thing that came out of this was found the battery box was getting a bit of rust on it so wire brushed and painted black, so that looks good.

Still not solved my problem though, so would be interested if any of the ablve would get any answers?

 

[chengny]

It still has I think the original high beams in the two bottom locations which are Wagner H4651 50watt. These are Halogen, does that sound correct?

Yes the lower lamps (high beams) are correct. They are 50W single filament. They draw 3.9 A @ 12.8 volts. So, 3.9 X 2 = 7.8 amps

As far as the dual filament (upper) lamps; the way the lights are wired - if the filament ratings are not equal - the lower wattage filament is used when the high beams are selected. Here is the diagram for a 1982 C/K with a quad headlight set-up:

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So, with your current dual filament lamps, toggling the dip switch to high beams de-energizes the 65W filament and powers the 55W via the light green 11 circuit.

55W @ 12.8 volts = 4.3 X 2 = 8.6 amps

The stock upper lamps (high/low beams) - the ones that you have in storage, do show as being H4656 - and are rated at 35/35 W. They draw 2.7 A @ 12.8 volts. Given that, 2.7 X 2 = 5.4 amps

Total amperage load - on high beams - with the lamps as currently installed = 16.4
" " installed at factory = 13.2


I don't know if that is conclusive. There isn't really that much of a difference. One would assume that GM anticipated upgrades in the headlights at some point and designed the circuitry to handle a slight increase in load.

On the other hand, my trucks have all had the 4 H/L set-up and never had a problem with excessive current. But, I always used lamps with the stock ratings (60/40 W on top and 50 W under). So, if highs were on, the total power load would be 180 watts @12.8 volts = 14.0 amps.

Maybe it isn't the circuit breaker in the H/L switch that is causing the power loss. It rarely happens but you might want to look at the two fusible link that feeds the headlight switch. It's in one of the two red wires connected to the "B" terminal of the starter solenoid - only about 2-3 inches away. Maybe try wiggling that fusible link with the headlights on and see if you get any reaction.

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[dtbnz]

As far as the dual filament (upper) lamps; the way the lights are wired - if the filament ratings are not equal - the lower wattage filament is used when the high beams are selected. Here is the diagram for a 1982 C/K with a quad headlight set-up:

After seeing the diagram, I noticed that my wires are not in the correct positions in the plug and the tan colour is at the top (middle position) light green at side and black on other side. (do not know how to load a photo yet)

It appears that it looks like the hi beam may have been on all the time and when the hi beam is selected the lower set of light come on as well. I never picked this up.
I changed them around as your diagram, and they now seems to work OK when selecting high beam both sets (4) of lights come on, with the Hi/Low set now diming to the lower wattage (55), and when selecting low beam the Hi/Low goes bright to the higher wattage (60) (however the lower set has a very very dim light showing when on low beam)?

I am going to see if I can get a set of lower wattage 30/30 forthe Hi/Low lamps and see if this helps.

 

[dtbnz]

I also check the Amps and it had dropped to 10Amps, so must be on to something here.

 

[chengny]

Yes, the color of the connected wiring (in relation to the terminal positions) is correct. But, it looks like (in this dwg) my comment about the small filament being the low beam is wrong:

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Should read like this:

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Which agrees with this:

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and this:

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And the lights should look like this:

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[dtbnz]

Ok so does this now mean that when selecting Hi beam the 65watt upper quad lights up or does the lower wattage light up?

Or is this still correct:

As far as the dual filament (upper) lamps; the way the lights are wired - if the filament ratings are not equal - the lower wattage filament is used when the high beams are selected.

?

Im assuming top quote and this is correct?
From one of your previous posts

The uppers are the only ones on when the low beams are selected.

They have dual filaments. On lows, the lower wattage filament is energized.

When you switch to highs; three things happen;

1. The lower wattage filament in the uppers is de-energized

2. The higher wattage filament in the uppers are energized

3. The lowers - which have only one filament - are energized.

I managed to order 60/40 watt Hi/Low today, so should have them in a couple of days and will fit and hopefully all Ok.

 

[dtbnz]

Looks like I just missed you as you posted the same as me.
If this does not work, i.e. wrong wattage lighting up 40 watt on full and 60 on low, the only thing this could be as someone suggested today, is that the Aussies have the connections on the lamps differently, and have the low beam at the top (middle).
Is there any way I can check this with out connecting to a battery, and using a meter?

 

[dtbnz]

Solved
I got new lamps and put them in and still had problems with lights now coming on on hi beam, but top set dim.
I left the light green in the middle on the connector, and swapped the tan and black arround. Tried and that side worked, so did the same on other side and all OK. Ran engine on idle for half an hour with hi beam and they did not flicker at all.

One interesting thing I found was the original USA lamps the connectors are the other way round from the ones I bought in NZ (and yes they are both facing the right way with the letters correct at the front). see picture.
I do not know if this may have added to confusion, but my wiring for the black and tan is the opposite way round from the electrical circuit above.
Anyway thanks for all the advise I received, with the information I received from this forum, made me nut it out and find a solution.

 

[Davey]

Thanks for all the info on this problem. I was able to fix my flashing headlights.
My initial problem was intermittent headlights that seemed to be affected by the hi/lo dimmer switch. I got busy on Amazon and ordered a switch. Well, I ordered the wrong switch and got the main headlight switch. I put it in and it didn't fix the problem. No headlights. I got a dimmer switch and put it in and now I could get the headlights to come on for less than a minute and they would start pulsing off and on and then they would go off and stay off.
I followed all the troubleshooting mentioned here and found I was drawing 14 amps with high beams. I checked the amps on each headlight, checked for a short to ground on the high and low wires, and cleaned and dielectric greased all the headlight connections and the firewall connector.
Still no fix. It was still acting like the breaker in the main headlight switch was tripping and resetting and finally overheating and staying open. It would even do it with only one or two headlights connected.
Completely out of ideas, I put the original headlight switch back in.
That fixed it.
I think my original idea of it being the dimmer switch was correct and this cheapo Amazon switch induced the "flashing" problem.
Man that was a pain!
But, one good thing, my clock started working again after cleaning up the firewall connector!

Thanks again.