starfire

1949 98 4-door 6-volt system.

Turn the headlights on with car off and they come on bright for about 2 seconds then they dim and flicker (parking lights and tail lights also). Ammeter goes crazy bouncing back and forth in the -30 to 0 range.

Car running and turn on the headlights and the same thing happens only with out the delay.

Turn just parking lights on and they and the tail lights do this and the ammeter goes crazy.

Turn signals and brake lights work just fine.

Where do I start?

Car has a brand new voltage regulator, but this was happening before the VR was replaced.

Thanks,

Oldsguy

Look at the light switch. It may have poor/loose/corroded contacts which are causing that sporadic current. The turn signals and brake lamps can be activated by different switches. It would help you immensely if you could get a wiring diagram for your car too, it would help troubleshooting so much. I hope this helps and you can find the trouble and fix it.

MDchanic

Sounds like a short in the feed to the head / taillights with the circuit breaker oscillating.

Fords of that era had the circuit breaker attached to the electrical panel on the firewall under the dash, inside of a roughly 1x3x3" cagelike box - I don't know about GMs.

Good luck!

- Eric

starfire

I suspect the headlight switch too. The 49's did not have a fuse or electrical box, it seems most everything is run through the headlight switch. I've ordered a new one from Fusick and will see. I have the wiring diagram, I'm just not very good with those.

Thanks for the help guys.

Oldsguy

Good luck. I bet the switch will fix it.

starfire

OK, I've got two pictures of the light switch (sorry about how bad they are, bad light, cell phone, and tired arms up under the dashboard do not make a good picture) and a copy of the wiring diagram. It looks to me like the switch is wired wrong. The wiring diagram shows a 10 gauge wire with a red tracer coming in to the center lug on the back of the switch, but the switch itself has what I believe to be the 10 gauge wire going to the #4 lug on the side. Anyone in agreement with me that the 10 gauge wire is in the wrong place? I can't tell if the tracer on the big wire in the pic is red or not (one of my daughters tells me it's black).

Looking at the wiring diagram (I'm terrible with these things) does it seem right that I should be able to tell if the big wire in the pic is the one that should go to the center lug in the back of the switch by running a continuity check from the battery end of the positive battery cable to the switch end of the big wire?

Once again, any help is appreciated. Of course the wires are mostly so short I can't work on the switch from a decent position, I have to be on my back with the brake pedal crushing the side of my
head

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MDchanic

I can't tell anything because I can't even get a really good look at all those wires, plus I have no idea where each of them goes, and many are the same color.
It doesn't look like what the diagram says it should look like, though.

Is that a replacement harness? If so, the colors are sometimes different, and that'll throw you right off right away.

You need to identify what each of those wires is, and label each one with a piece of tape, then you can determine which one goes where.

- Eric

Oldsguy

I did what you are about to do with a slight variation. I bought a basic fuse box and wired everything through it and then bought a generic light switch and wired only what I wanted to operate from it which were the headlamps and running lights. It was a pain and took a lot of conscientious effort. As Eric said, you need to know what every wire does before you take it apart though and label them.

Ozzie

Try the new switch; if it cures the problem ------great! If it doesn't, I tend to agree with Eric that there is a short in one of the light circuits. It looks like:
16BCT does the tail lights (not the stop lamp, which is unaffected)
16N does the front parking lights
16GT does the low beam
14BCT does the high beam
18B does the panel lights
You could switch between low and high beam and see if it makes any difference since they are two different circuits. If it resolves, the problem is in the other circuit.
If none of this solves the problem, you may have to try to isolate the problem. Disconnect all circuits at the switch which are fed when the problem occurs. Reconnect one at a time. When you get to the problem circuit, the problem will start again. Then trace out the problem circuit. It could be a worn through insulator where 64 years of friction did damage. If you get it resolved, I'd like to hear what it was.

starfire

OK, first I replaced the dimmer switch (it was cheap and was easier to do), but that did not correct the problem. So I took all of the wires off the old switch. The one I thought was 10 gauge was actually the 12 gauge from the dimmer switch. I found the 10 gauge wire and confirmed continuity with the + battery cable. Went to hook the wire up to the BRAND NEW headlight switch I had bought from Fusick and the damn thing just fell apart!?!?!?!? The tabs that hold the body of the switch together are made out of such cheap metal that they just let go of the other part. So now, because even though I can put the new switch back together, I don't trust it any farther than I can throw the car, I have to hope the old switch is not the problem. So I take the old switch and hook the power wire up to the rear middle lug. Then I take the 12 gauge wire from the dimmer switch and I hook that to lug # 4. Hook the battery up and voila! headlights work without flickering. Push the dimmer switch and we have bright lights! Push it again and we have regular lights. Next I am able to identify the wires for the back up lights (but the wiring diagram does not show where they go, so I just labeled it well and tied it up out of the way), and then the glovebox, and underhood light, but as I'm not concerned about them right now either I labeled them and tucked them away. Next I was able to figure out the tail lights, hooked them up where they belonged on lug 3 and we had tail lights. Tried the headlights and they worked fine. After much searching and many false leads, I finally found the stop light wire, hooked that up to the fused lug and we had stop lights. Tried the headlights and they worked fine. I decided that since we had headlights, tail lights, and stop lights, which are all that are needed for safe driving, we would stop at that point. My next project is to figure out which wire is for the instrument lights and which one is for the parking lights. Then eventually get the rest of them hooked up. Right now I suspect the problem we were originally having (headlights flickering) has something to do with the fog lights (factory or dealer installed). I will eventually try to hook them up also.

Thanks for all of the information and ideas!

MDchanic

Fantastic! Glad you got it working!

- Eric

Allan R

From the sounds of it, just leave the fog lights out of the circuit, but hook up the dash lights for sure. Chances are you're not going to do a lot of night time driving, but dash lights really help when you do. Fog lights?? Naw - they were just an option in the first place.

Congrats on doing your troubleshooting and working methodically. It seems to have really paid off!

EDIT: just went back and looked at those pictures again. HOLY MOLY! Eric? Many are the same color??? Nailed it bud. They ALL pretty much look the same. No wonder manufacturers went to color coding wires! That looks like a friggin nightmare!

MDchanic

Thanks, Allan. There are subtle differences between wires in person, but trying to see them all will make your eyeballs bleed.

- Eric

Allan R

oldcutlass

I worked on aircraft electrical and avionics for many years, all the wires are white or tan. They either have source/destination codes or a wire number. Did it for years but you have to have a wiring diagram.

starfire

Yeah, I'm not good with colors (a little red/green color blindness),but even my daughter who is great with colors was baffled. It should be easy, but even the wires that are supposed to be either red or black, she just shook her head and said "sorry Dad, they just look brown". The natural wires with the red, black, or green tracers, all the tracers look brown too.

The instrument lights are next as I agree, they may be needed at times. I will eventually get the fog lights working, but that will be a "someday" project.

I have to say I was thrilled to have successfully got the lights working. Thanks again for the help and support. How did people ever get things done before the internet. Thank goodness for Al Gore

Allan R

Umm, that must play hell on you at a traffic light! GO!! NO, STOP! Sorry, it was just there and it seemed like a one liner opening.

On the serious side, red/green according to Ishihara or did you take the Holmgrem test (functional). Most people I know with color blindness memorize the location of the red/green on the light display. It works for them in areas they are familiar with.....

starfire

Actually I can see the red light ok, but the green lights are white. Gives me trouble at night as I can't see that there is a traffic light amongst the mercury vapor lights (also white to me).

I don't know what the test is called, but I can't see the number inside the circle of dots.

Allan R

Dots? Circles? Numbers?? Man I don't even see that! When I got my new prescription glasses I was driving at night and it was really difficult. Every set of lights was like 2 of everything and weird colors too. Went back to my old glasses because they work. You been color blind all your life or it just sneak up on you?

starfire

All my life. Didn't really notice until high school biology when we were looking at things in the microscope and I couldn't see things I should have been able to. We discovered that I couldn't see them because of the color of the stain. Had a bitch of a time dissecting too. So many things identified by color.

BTW, peanut butter is green to me. I can't see the orange golf ***** in grass, but I can see the white ones and bright green ones just fine.

Here's the Ishihara test:

http://www.toledo-bend.com/colorblind/Ishihara.asp

I fail it perfectly. I see the 25 and 56 plain as day and nothing but random dots in the other ones.