Yes, If you have either a meter or a test light you can verify if the switch is bad, but the switch has to be removed from the dash, which is actually the hardest part. It sounds like you're throwing in the towel, but if you want to continue troubleshooting, let us know. For tonight, I'm guessing that you'll have to find another solution to get her home (maybe have a friend drive in front of you, or a tow). Or, if you can find a nice size wire (12 gauge), you could in theory run a wire from the battery to the tan wire at the dimmer switch to get headlights (but you might not have tail lights either, in which case this might not help). Remember, it's a 50 year old car, so it IS going to have issues occasionally.

 

I meant the dimmer switch, it seems that the headlight switch is working OK, at least the dashboard lights still come on.

 

I think your dimmer switch looked like crap, but worked. Your problem seems to be downstream.

 

The dash lights are actually a separate part of the headlight switch, so they could work when the headlights don't (and vice-versa). To verify the headlight switch, you should have 11-13 volts on the blue wire at the dimmer switch when the headlights are on. If you don't, then the problem is not the dimmer switch (but could be headlight switch or you're not getting voltage to the switch). If you DO have voltage on the blue wire, then the headlight switch is good.

 

P.S. You seemed to indicate you may have a meter? Let us know, or if you don't you can get a cheap test light for around $10 or under.

 

Yes, but the original issue was that the lights worked fine unless I touched the dimmer, just a mere brush of the side and the lights would go out. That says a short in the dimmer to my mind.

I can work with that info.

I have one at work, I’ll borrow it tomorrow.

 

Your fusible link is down by the starter, it looks like this:


Find the starter solenoid on page 1 of the schematic and follow the red wire down to the 'fusible link'.

Let's see if you have power coming into the light switch.

 

Hi Peterbuilt - You're one of the forum members who I know knows electrical, but I THINK if that fusible link was blown, then he wouldn't have any power to the rest of the car? And I THINK (and I might be wrong) that once you get past that fusible link, there are no other fuses/links, etc for the headlights other than the breaker in the switch? If I'm wrong, let me know (it wouldn't be the first time....or the second...or the...)

I do agree that he needs to verify power to the switch. I forget if the dash lights have a separate power feed than the headlights, but I think they might? I'll spend a few minutes in the morning going over the schematic.

 

Yes! if the fusible link by the starter is good then your need to check the one at the horn relay
See 'Horn Relay' on page 2.
Before you do that check the new high beam switch at each terminal to see if it failed and sent power to ground.

 

Don't know how to do that. even if I could find what you're talking about, I don't know how to check it for power.

How do I check the high beam terminals as you suggest?

 

How I usually do it is to first inspect it to see if it looks melted or burned. If it looks ok, then I poke a safety pin thru the wire insulation on the side 'away' from the battery to check for voltage. Don't stick the pin into the actual fusible link, but into the wire a few inches past the round rubber connector. Once I'm done, I wrap a small piece of electrical tape over the pin hole. Note that the fusible links usually have those round rubber chunks at each end of it as in PeterBuilt's picture (unless it's been replaced in the past). The fusible link in his picture actually looks in pretty sorry shape, and is probably bad (note the distorted covering at each end).

Here's what I recommend:
1. Check for voltage at the blue wire on the dimmer switch when the headlight switch is 'on'. That will tell us if we need to look further back (fusible links, headlight switch, etc). If you have power there, then the problem is probably at the dimmer switch.
2. If no voltage at the blue wire, find the fusible link next to the horn relay (under the hood, driver's side fender). If you're not sure which is the fusible link, just post a picture of the area, and we'll point you in the right direction.

Also, let us know if you're familiar with the meter you get from work. You'll need to set it to read DC volts to check for power, and ohms or continuity for checking the dimmer switch functionality. If you're unsure, just post a pic of the meter too.

 

Okay, so engine on. Headlight switch on. Check blue wire for 11 to 13 volts. Will do.

I tested the switch, and it seems to be working okay. I get tone on top pin and one side or the other as I click the switch. I don't think it really does anything else right?

Off between 1 and 2 PM EST today so will post results after that.

I work on computers so I'm good with the multimeter. I just seem to have a bad time with cars.

 

Correct, the dimmer switch just directs the voltage to one of the two terminals. When you're checking the voltage on the blue wire that connects to the dimmer switch, make sure you get good contact with the meter probe. The way your old dimmer switch looked, the connectors might be corroded also? I'd connect the ground cable on the meter right to the battery ground, just to play it safe, unless you can find a good (confirmed) ground that's easier to reach. If you can, post a picture of your dimmer switch connector, so we can see what condition it's in.

Also, I only see one power connection to the headlight switch, so check the following to see which of these still work: tail lights, side marker lights, dash lights, interior dome/footwell lights. If any of them still work, then your power TO the switch should be good.

 

Less than .1V coming in to the blue wire.
Can't tell you about tail lights, but blinkers, dash lights, and footwell lights all still work fine.

Pic of my harness connector:



Pic of the only wires I could find on the drivers side fender:

 

OK, the connector actually looks pretty good. I did some more research, and I think there ARE two voltage sources coming into the headlight switch (I thought that was the case, but initially couldn't find it in the diagram). So now we need to verify your fusible links. The hardest one to get to (by the starter), should be OK, because if that burns out, the whole car is basically dead. This leaves two that are in the area that you took a picture of. Below is a picture of my horn relay. Both of the screw terminals (labeled A & B) should have 11-13 volts (battery voltage) on them at all times (even with key off) - at least my 69 does. If you're not seeing battery voltage on those two terminals, then let us know. You can use either the master cylinder or the alternator case for a ground point.

Terminal B is where the two fusible links attach to - one should be orange and one is black). You'll have to follow those to where they enter the wire harness and expose a couple of inches of the wire. I THINK it's the black fusible link that supplies the headlight power, so check that first. Once you have a couple of inches of wire exposed, I usually use a safety pin to poke thru the wire insulation and then use the meter to see if there is voltage on that side of the fusible link. The fusible link 'ends' at the round rubber looking thing.

 

Okay, new pic, this is oriented correctly, so top screw is above bottom screw as it sits in my car. Both screws get 12.3V with key on, nothing with key off.
Top screw goes to a thin black and dirty red wire that have a rubber boot about 5 inches out from the screw. Bottom screw goes to a thick red wire that I don't see a boot on.
When you say expose wire from the harness, do you just mean any wire past the boot on the side away from the screw?

 

Yes, follow the black wire (fusible link) from the screw terminal to the rubber boot, then insert a pin in that wire anyplace after the boot. The key needing to be on to get voltage here might be something that changed after 69, but this also means that your headlights won't come on unless the key is 'on', which doesn't sound right either (even our 79 allows the headlights to be turned on without the key).

Basically, the fusible link functions like a wire when it is 'good', so if there is voltage on the screw terminal, there should also be voltage after the rubber boot also (unless the link 'burned open' inside of the insulation).

 

Out to dinner right now, will check it when I get home.
Question is, if it burned up, what caused it and will it just happen again?
And how do you replace those links?

 

Normally they only burn up if something was drawing too much current. You mentioned something earlier about 'the battery gauge went crazy'? That could have been when it happened. Were your headlights on during that time? You also said your 'door open' light was flickering - was that the 'headlight door' light? If so, that should only come on when the blue wire going to the dimmer switch has power (such as when the headlights are on).

Replacing the links by the horn relay aren't too difficult, but you will need either a crimper or a soldering iron (I prefer to solder and seal it up with shrink tubing, but a crimp connector will suffice if you're not handy with a soldering iron. Most auto parts stores sell the replacement fusible links - I THINK the black one is a 16 gauge link, but you'd need to verify that first.

 

They were not on. The volt gauge went all the way to the right as I clicked the dimmer switch 2 or 3 times. Engine was running.
No, it's my 'Door ajar' light. The one that comes on when I open the drivers or passenger door.

So my links are black and red, but opposite coming out the other side of the boot. the black wire is red post boot, and vice versa. I'm home now so about to test them both.