Headlight switch help

[mattnduke]

Hi all,

Long time user of this site and finally bought my first EB. I couldn't be any prouder of a new papa. Been driving her the last month with no issue and then a week ago had my first hiccup- driving at night and my headlights go out. I was actually sort of excited. My first thing to fix. And it's an easy one!! I checked fuses at home, all good, no luck. I then realize the lights work with the high beams on. Drove her again the next night, and my high beams go out. Great... At least my two yellow driving/parking lights still worked.

I read many of the threads around the headlight switch and thought, aha!! Easy fix. Um,,,, no. Went to my local O'Reilly Auto, and they gave me the one that was supposed to fit. Nope. Easiest way to explain it is that my old switch had long prongs and the new one had short fatter ones. Went back and they found one in the system that said it was for an 1985, but had long prongs like my old ones. The only difference is that the new switch has a prong right in the middle and my old one doesn't. But, the old connector doesn't have anything wired in to it in the middle. I also grabbed the connector part from the store that plugs in to the headlight switch. I figured if the new switch didn't fit, I could just rewire to the new connector up and use my my new switch. Well, the switch fit in to my old connector, but my lights wouldn't turn on and my parking lights wouldn't turn on either. Only thing that worked was my dash/cluster lights.

Here's my conundrum. I could wire the aforementioned new wiring connector up, but the new connector wires aren't labeled and none of the colors on my old one match up. My old connector wires are labeled though. I'll be happy to share the colors of my new one, but I figured Ill wait for suggestions. It's a BWD brand and I couldn't find anything on line.

Also FYI, I hooked up my test light to all the wire inputs on my old connector. I wanted to make sure I had power to the switch to eliminate any other possible causes. Only 3 of them were hot- one labeled "HLS FEED" another labeled "PARK FEED" and another labeled "PARK SIDE". "DOME LIGHT", "HI DMR", and two labeled "PARK SIDE" were cold, as was the only one with a built in fuse, which goes to my dash/cluster lights. Does that sound right? I don't have a dome light.

Should I rewire it? If so, how do I know which wires go to what? Process of elimination? Or do I go store to store to find the exact switch as my old one? Sorry for the info overload, and many thanks in advance for the help and advice!

 

[BRONCROB]

I would try the dimmer switch first then get the correct dash switch if that doesn't work.

 

[mattnduke]

Funny thing is that I thought I would save myself a few trips to the store and bought a new dimmer switch on my last trip too. But the new one doesn't fit in the old wiring connector either. My prong inputs are closer together than the new ones are. Not sure if the PO used random parts on the rebuild or if O'Reilly's parts system is wrong. I'll grab another one though tomorrow when I figure out what to do about the switch.

Both times, the lights stopped working as I was driving down the road, not when being switched high or low. That's what made me think it was the standard problem of the internal part of the switch going out due to overload. Once I get this fixed, I'm definitely installing a relay to take the load off the switch!!

 

[PaveBronco]

Best place to get a lot of replacement parts are the specialty vendors Wild Horses, Toms, Duff’s, Jeff’s, BC Broncos, and a couple of others. They all have web sites so you can compare prices. I’d swap the dimmer switch like broncob suggested, and while you at it “hyghlndr” had a post in parts for sale, selling a relay headlight harness to eliminate the full amperage going through your headlight switch and overloading it.

 

[Broncobowsher]

If the high beams work and the lows don't, the headlight switch is good. It is the dimmer, wiring, or bulbs. And having both bulbs go at once is actually fairly common. They were usually built at the same time, in the same plant, have had the exact same use. When one goes, it drops a load off the circuit so the other bulb gets a little extra voltage, which is often enough to push the bulb over the edge and burn that bulb out as well.

Another option that may have been overlooked, voltage regulator. If it is stuck at full charge you could have over-voltage killed the bulbs. Won't be long until the battery is cooked to death. A volt meter on the battery as it is running (idle and 2000 RPM) and look for excessive voltage.

 

[DirtDonk]

Just so you know mattnduke, your EB sounds like it's been re-wired with an aftermarket harness. Factory wires don't have labels, just color codes.
Do most (or all) of your wires have solid colors, or are there lots of stripes and such?

What does the fuse panel say? Have a name easily visible, or if not, can you post a picture of it? Is it in the glovebox?
Oh, and what year is your Bronco?

With many of the harnesses, they use the later model Ford light switches. It's very possible that this is why your floor dimmer switch doesn't fit either. Sorry I'm not at the shop for the rest of the week, but I'd be happy to measure some of the switch contacts and spacing on the different harnesses if that would help. Probably not needed, but not a problem if you need that comparison.

Usually they just substitute the headlight switch because some consider the newer ones better designed, but mostly because the factory connectors are no longer reproduced, so it's just easier to use what you can get when making a new harness. Maybe Eric from Painless can comment on that, as he designed the new Painless harness.
Do your wire labels include numbers and look to be in Ford colors? Then it's Painless.
If they appear to be GM color codes (mostly solid colors, and no numbers) then it's one of the other companies offerings.

A Purple ("Violet") wire at the starter relay under the hood would be a dead giveaway.

Good luck with the light issue. Bad switches are more common than they should be when new. But like was said, check your bulbs first. Then your wires. Especially the grounds.
Then, if that doesn't pan out, go back to the switches.

Paul

 

[mattnduke]

Thanks for all of the repelies. Great info. My bronc is a 72. The harness wires on there are all solid colored, no numbers. Just the label on the wire itself.

I was on Tom's Bronco Parts website and saw that they had two headlights switches on there. One was a standard replacement and the other was for a Centech wiring harness. I've got the Centech harness. I didn't realize there was a specific headlight switch for the Centech. I ordered that along with a new dimmer switch from TBP. I'm going to wait for those to get here and try em. They should be here any day. I'm crossing my fingers that those fix it. If not, I'll try the new bulbs, which I should have done in the first place. I didn't think it would be them because lows went out at the same time, and then highs went out, but it makes why they would go out together.

I ordered relay from Hyghlndr too. Thanks for the tip! I'll post what I come up with once the parts get here.

 

[mattnduke]

Alrighty. So I ended up having power at my light plugs. Bulbs went out at the same time. Feel like a dummy for not checking there first. But at least now I have a spare dimmer and headlight switch.

So I put new lights in voila, lights. Took her for a drive tonight. I noticed that as I was gearing up, my dash and headlights were getting brighter, and vice versa. Decided to flip the high beams on. They turned on and then went out. Damn. Clicked over to low beams and those work. Least I still had something to get me home. So what do you guys think? Voltage regulator going bad? How much voltage is normal?

 

[DirtDonk]

...I noticed that as I was gearing up, my dash and headlights were getting brighter, and vice versa.

The dimming/brightening could be a sign of a bad voltage regulator, a weak alternator, or bad connections hereabouts.

Decided to flip the high beams on. They turned on and then went out. Damn. Clicked over to low beams and those work.

Voltage regulator going bad?

Only for the flickering or changing brightness of the lights. In other words, voltage not consistent. But then again, it could be those other things I mentioned too.

How much voltage is normal?

When the engine is off, the battery itself should read in the low to mid-12 volt range. 12.4 is common.
When running though, the voltage should go to, and stay at, near the 14v level. 14.5 is common with a good alternator.
Anything over 13.5 is considered acceptable on an older vehicle, but anything under would be suspect that something's not right.

Since you have a relatively new wiring harness, the wires themselves should be in good shape (hopefully) for now.
What type of alternator do you have? If you're not sure, can you post a pic of it?
How is it wired? In other words, is the larger Yellow "ALT +" wire coming off the back of the alt at the "BAT" terminal? Or has a larger wire been substituted that runs directly to the battery or comparable location?
Have you come across any questionable connections that might indicate a general lack of care when the harness was installed? It's possible for a loose or corroded terminal or connection or splice to be causing some issues.

If it's a high output alternator and the Yellow wire is used exclusively, I would pop my head under the dash and take a close peek at the back of the fuse panel in the glovebox. Look for any burned looking connections or wires.

This is just general stuff. Nothing that's going to immediately make the problem with your lights known. But it could start to clear up little things like the dimming dash lights and such.
That could be as simple as a 20 dollar voltage regulator. Or not...

Good luck.

Paul

 

[Viperwolf1]

Could still have a bad dimmer. They sit in a bad location and tend to get lots of moisture there. I'd swap it out.

 

[bronco t]

Alrighty. So I ended up having power at my light plugs. Bulbs went out at the same time. Feel like a dummy for not checking there first. But at least now I have a spare dimmer and headlight switch.

So I put new lights in voila, lights. Took her for a drive tonight. I noticed that as I was gearing up, my dash and headlights were getting brighter, and vice versa. Decided to flip the high beams on. They turned on and then went out. Damn. Clicked over to low beams and those work. Least I still had something to get me home. So what do you guys think? Voltage regulator going bad? How much voltage is normal?

Sounds like a grounding issue. Check to see that your headlight harness is grounded properly. I had a similar problem only to find my headlight harness ground was funky. My ground was attached to the radiator core support at each headlight.

A volt meter will read voltage with no load, but with a bad ground the voltage will fall off when the load is applied.


Good luck.