1967 Eldorado headlights did not work

As we had a very nice evening I wanted to take the 67 Eldorado for a spin.
When I took the car out of the garage I noticed that the headlights did not come on, but the taillights worked.

I suspected that the light switch must be the problem... I unplugged the connector of the switch and tested if 12V power was coming to the switch through the wiring.
There was one hot wire and I connected it directly to the headlights and they came on.

I then wrongfully assumed that the switch must be the problem then...
So I decided to take it out and inspect it.

Getting this switch out is a real pain as there is one screw thats almost impossible to reach. You can only get to the switch from underneath the dash btw...
It took me a couple of hours to get it out lying on my back under the dash...

I then opened up the switch and when I opened it up it fell apart immediately. I had a really hard time getting it back together correctly. Before that I cleaned everything inside.
I measured it with the multimeter and everything was fine.
Getting the switch back into the car was even more difficult than taking it out... There is this one d*mn screw thats almost impossible to get back in. Try to avoid to take the switch out, as you can measure if it works with the multimeter. I did not read the electrical diagrams carefully enough, so I did not measure it correctly and so I took it out.

!!! Be aware that the headlight switch on the 67 Eldorado is almost impossible to find, as it is a very special switch with the vacuum valves! If yours has twilight or auto dimming its even harder to come by!!!

As it turned out my switch was o.k. and the headlights did not work for another unknown reason... So I googled the problem and to my surprise I found my own website with a solution!
I had completely forgotten that I had the very same problem with my headlights a couple of years before and found a solution back then. I was just lucky that I do use my website as a sort of diary for the repairs I do on my cars.

As it turned out the same fusible link had burned through again. It runs very closely to the headers to the starter on the positive battery cable. Maybe it got too hot and failed or just broke apart. I could not see any melting or signs that it had burned through. It looked fully intact from the outside and I could only see that it was defective when I removed the insulation...

To replace the fusible link you have to take out the positive battery cable and replace the fusible link. Thats not a big deal. I rerouted the cables a little bit this time and hope that it wont fail again.

The 1967 headlight switch with automatic dimming
the light switch out of the car
Seen from the side - you can see the vacuum valves

Be very careful if you take the switch apart - as some parts will fall out...

The red cable on top is a fusible link and it caused the problem. I could not see from the outside that it was broken under the insulation.

The headlights are back in working order


The 1967 Eldorado headlight door repairs - first spring outing

As we had an unusual warm day today with the snow melting in front of the garage, and having a couple of hours of spare time at hand, I decided to drive the Eldorados out of the garage. They both started right up as soon as the fuel pump delivered fuel to the fuel bowl. Both cars idled beautifully and it was a pleasure to see them in the bright daylight again for the first time since last October when I had put them into storage.

While I had the 67 Eldorado out I also turned on the headlights and was once again annoyed by the fact that the right one opened simultaneously, but closed slightly slower than the left one when I turned the lights off. There was a difference of around 1 second in movement between the two headlight doors.
Being a perfectionist I could not stand this, so I began searching for the problem. I already had spent some time in the past trying to fix this, but I did not succeed. The system is driven by vacuum only, so I started to look through the vacuum hoses once again. I had already exchanged a couple of them last year. I found another two brittle ones going through the firewall to the headlight switch from where a slight hissing sound was coming when the lights were on. When I touched them the hissing would become even more noticeable. I then tried to press them onto the connector of the switch and the first hose began to crumble into pieces. So I replaced all the hoses on the switch and rerouted them through firewall through the rubber insulation. There are three hoses . One is the vacuum feed (the one in the middle - I think it was yellow), one is for opening the doors (green) and one for closing (red). I also replaced the red hose behind the firewall going to a T-connector from where the vacuum is fed to the headlight door actuators. I had already replaced the two hoses after the T-connector in the past. With all new hoses in place the doors now perform almost simultaneously and quite fast. So when you run into troubles with your headlight doors, check and replace all the according vacuum hoses first. Its amazing how brittle the hoses going to the headlight switch inside the car can become over the years. It looks like they used a quite different material for these three hoses, as all other vacuum hoses are in much better shape and do not show any sign of deterioration at all.
You can see a video of the headlight doors in action below. On this video they are slightly out of sync. As it looks like they are slightly different every day, depending on temperature and engine idle...

watch on youtube or below


the vacuum diagram for the headlight doors

The vacuum diagram for the headlight doors

While the Eldorados were outside the garage my wife used the opportunity to shoot a couple of pictures she had in her mind, which she is planning to hang into the kids room. Cant wait until the medium format film is back from the photo lab. Below you can see only some digital snap shots I took.
Despite the last two unusual warm and beautiful days unfortunately winter is not over yet here in Austria, as some more snow is predicted for next week and the cars are back in the garage desperately waiting for April to come...

The Eldorado is enjoying some sun rays for the first time this year
Although she is 7 months pregnant, my wife Afra is still climbing ladders to get the best angle for her shots...
The two Eldorados in front of the garage where the snow has just melted away.


Visiting the 67 Eldorado at the restoration shop

Today I visited the 1967 Cadillac Eldorado at the restoration shop where some crucial work is done to it to get it back on the road. The guys are doing a lot of progress. I snapped a couple of pictures with my cell phone while I was there.
Here are some pictures of what is going on in the shop. You can also see all the restoration pictures here!

The 1967 Eldorado at the lift - the trunk is full of parts

Look how clean the 429 engine looks inside - it only has 27k miles on it - the valve covers will get a repaint and new gaskets will be installed

The radiator is out for re-coring

The left front disc brake is sticking a little - it will be completely overhauled as well soon.

Some of the parts - the old ball joints are out. New brake hoses and brake parts are waiting for installation.

New H4 headlights had to be installed as the original T3 headlights are not street legal in Austria


1967 Eldorado - the headlights and the ALC work again

Yesterday I finally found the time to spend a couple of hours in the garage and deal with the problem of the non working headlights and the defective ALC of my 67 Eldorado. I got some great tips from Glen (see a couple of entries below). With his great expertise I could solve all the problems. I installed a set of new original style spring clamp battery cables from Antique Auto Battery and repaired the blown fusible link for the headlights. The new battery cable comes pretty close to the original cables that came with the car. I would say they are 98% correct.
I also got a new control valve for the ALC compressor from Arizona Vintage Parts (a company I highly recommend). With this new valve the ALC is back in working order and the car is now raising its rear to the correct riding height again.

the new original style spring clamp battery cables

a new used ALC control valve is also in place.



As my headlight suddenly stopped working recently, (see two posts below) I spent the afternoon in the garage for troubleshooting. I got a very good troubleshooting guide from a fellow Cadillac enthusiast from the USA.
Glen wrote the following:
“If you take the panel under the steering column off I think you can reach up and disconnect the connector from the light switch. Or you maybe able to get a meter probe up there to check voltage. The battery connection to the switch for the headlights is on the 14 gauge yellow wire. This only supplies the headlights and front parking lights. If you have 12 volts there then your problem is in the switch. There is a circuit breaker in the switch and it may be bad or the contacts in the switch are bad. IIRC these switches have a vacuum switch on the side that operates the headlight doors. This makes them hard to find. They do not interchange with the 68 Eldorado because in 67 the parking lights only come on when the switch is pulled out to the first position while in 68 the parking lights come on with the headlights also. If you do not have voltage on the yellow wire then you should check the fusible link on the starter. It is an 18 gauge dark green wire that changes to a 14 gauge red with white tracer before it gets to the connector. Check for 12 volts at the connector and check the contacts in the connector. “

Glen was spot on with his diagnose and it turned out that the green 18 gauge fusible link was the culprit for my headlight problem as it came apart for unknown reasons.

the green wire once was a fusible link - it fell into pieces when I slightly pulled on it

As a follow-up Glen recommended the following:

“You might want to look closely at the break in the link. See if it is melted or did was it broken by mechanical means. If it was just pulled apart or cut then you have to check what caused that. To trouble shoot this if it was actually melted due to over current, I would unplug the headlights and front parking lights, and temporarily connect a headlight or other big light bulb, in place of the fusible link. You can then try things without blowing fuses. With the troubleshooting light in place it will light up brightly if there is a direct short. With the headlights and front parking lights disconnected the test light should not light up at all under any condition. You should be able to move change the position of the headlight switch, switch from high to low beam (light switch in the headlight position); wiggle the wire harness anywhere and not light up the test light. If it does you have found the short.”

I did this procedure today but it did not show any shorts. I then reconnected the front lights and everything did work again. I will now have to find a replacement fusible link which is very uncommon over here in Europe. I will replace it together with the positive battery cable where the clamp is almost falling apart. I hope the issue wont come back. It looks like the fusible link maybe only fell apart due to age as it did not show any signs of burning. Its located very close to the starter and the exhaust manifold - so maybe 42 years of dirt and heat just made it crumble into pieces....

the completely removed positive battery cable harness
the original battery clamp - its already missing the spring part

The starting circuit diagram is showing the battery cables - Click for larger picture!

The Iginition and Starter Circuit Diagram for the Eldorado (693) and the other Cadillacs of 1967.
Click for larger version!


1967 Eldorado Inspection - ALC issues and dead headlights

I took my 67 Eldorado to my restoration shop yesterday to have it checked for the Austrian registration.
When I arrived there the headlights did no longer work. They did not have any problem before.
When the inspector wanted to turn them on - the headlight doors did open but the lights did not come on.
Also the parking lights and high beams do no longer work. The taillights did come on though and the cornering lights and turn signal do work as well.
Very strange… Checking the fuse panel I found out that there is no fuse for the headlights. My guess is now that it must be the headlight switch - can this be repaired? The shop manual mentions a 25amp circuit breaker in the switch but it does not mention how to repair it or check it.

The other thing which stopped working yesterday was the Automatic Level Control. The vacuum operated compressor in the engine bay seems to work as I can hear a ticking noise, but the car does not raise. I also added some pressure (100psi) to the service valve at the compressor but the rear of the car did not raise at all. When I depressurized the compressor the car did not come down any further either. Very strange… I really need to get this fixed - non working parts are making me crazy!
The car lost the yellow plastic cap which is located on the top of the regulator valve while driving it into the shop. Unfortunately it landed directly below one of the tires and was crushed to tiny little pieces. I will have to try to find a replacement. I have no idea how this could have come loose.

The car did not pass the inspection for some other reasons as well , like a sticky front disc brake, worn ball joints and pitman arm and some other minor things . It will keep me busy repairing all this for a while. Whats worrying me most is the headlights and the ALC as I do not have any clue at all.
On the positive side - the car was a pleasure to drive the 60 miles to the shop - its so much different to the “regular” Cadillacs - Big, silent and powerful and no big boat ride ;-)

in the shop