jaunty75

I have a weird electrical problem with my '67 Delta 88. The taillights (not the brake lights) go on whenever one merely puts the key in the ON position or with the car running. The headlights go on as they should, only when the headlight switch is pulled out. I cannot make the taillights go out at all unless I turn the car off.

I think the problem is in the headlight switch because there is another peculiarity in that the instrument panel lights that go on when you put the headlights on are sometimes on all the time, not just when the headlights are on. Other times they work as they should and go on only when the headlights are switched on. You can kind of switch between the two by jiggling the switch, which isn't really a good sign. This second issue actually explains a problem we had early on with the battery running down even though the car was off and everything was switched off. The instrument panel lights aren't that easy to see in daylight, so we hadn't noticed that they were on.

The other interesting thing that suggests something loose or whatever in the switch is that, when we drove the car home when I first purchased it about a month ago, my wife followed me home. We drove home in the daytime, and she does not remember the taillights being on, which is something we both think she would have noticed and commented on at the time. So something has happened in the meantime to cause this to start happening. Again something loose or intermittent in the switch comes to mind.

Anyway, I have the service manual, but it doesn't really explain removal of the switch. There is a sort of an exploded view diagram of the dash showing the switch with an escutcheon and the **** and wires protruding out the back, but, for example, does the **** just pull off or unscrew? What about the wires connected to the back? They're in a big plug that one apparently pulls off, but do you just yank hard, or is there some kind of plastic tab that you press in and then yank hard? Is there more than one plug? Does the escutcheon unscrew, or is it pressed on?

Assuming I get it off, is a headlight switch take-apartable and/or rebuildable? If not, anyone have a suggestion on where to get another one? Are they interchangeable with other years or other '67s (like a 98)? I would think both.

Thanks for any advice anyone has!

joe_padavano

The lights do not get power from the ignition switch - they work whether the key is off or on. As a result, I don't see how this can be related to switched power unless there is another short someplace else. There should be no switched power that runs through the headlight switch. Are you sure it's the tail light filaments that come on and not the brake/turn filaments? If the latter, then that makes more sense. The turn signals DO get power from the ignition switch and a bad turn signal switch would exhibit the symptoms you describe.

jaunty75

Thanks. I did occur to me that there is nothing about the operation of the headlights or the headlight switch that requires the key to be in the ON position.

I checked, and it really is the taillights and not the brake lights or turn-signal lights that light up.

Possibly it's something that turns on with the ignition switch but whose ground is bad so it's finding ground through the tail lights. I guess I could disconnect the tail lights, turn on the ignition, and see what, if anything, doesn't work.

Some other questions and observations. Remember, I've had this car only about a month, and I'm still finding things I didn't notice before.

You mentioned the turn signals. They work fine. However, I discovered that this car's emergency flasher system is inoperative. The little button that sticks out the right side of the steering column that you push in to engage the flashers is missing. There's just a screw hole there, so I screwed in a screw and can now push in and pull out the switch. When I push it in, the flashers do not come on and I don't hear any clicking or anything, but the turn signals stop working, which I think is correct. It's possible the flasher unit is broken or missing altogether. Where under the dash is it, and what does it look like?

Another couple of questions as I'm still thinking of possible sources of grounding problems. First, where is the negative battery cable's back end (the end that does not connect to the battery) supposed to attach? In my car, it's attached to one of the power steering pump mounting bolts, but it occurs to me that this might not be right. Shouldn't it be attached directly to the block somewhere? Not that the power steering pump isn't well connected electrically to the block, but might as well make things as correct as they're supposed to be.

Second, I checked the cowl-to-engine-block ground strap, and, while it's not the prettiest thing I've ever laid eyes on, it is there and appears solid, although it might be a bit thin at one end and is as filthy as all get out. Perhaps replacing that would be a good idea. Are there any other ground straps elsewhere in the car?

Another electrical weirdness is the GEN light on the dash. It's supposed to glow a dull red if you put the ignition switch in the ACC position. Sometimes it does that and sometimes it doesn't.

Also, sometimes the GEN light glows a bright red if I turn on the headlights with the ignition off, and other times it doesn't glow at all with the lights on and the ignition off. I don't think it's supposed to glow when the headlights are switched on with the engine off.

The gas gauge does not work and did not when I got the car. Given all the electrical weirdness, I'm first suspecting an electrical connection issue instead of a bad sending unit, but really don't know.

As I understand it, the HOT, COLD, GEN, and OIL lights should glow briefly and then go out when the car is started. Well, none of them ever goes on when I start the car, and they never have. As I noted above, I have seen the GEN light go on at other times. The oil pressure sending unit is disconnected, so I can explain that one, but I just replaced the temperature sending unit and reconnected the wires, but no dice. To test that light, what do I need to do? Disconnect the wires from the sending unit and ground them? (There are two--I'm guessing one for the COLD and the other for the HOT?)

By the way, I checked all the bulbs on the dash (the panel illumination lights as well as the HOT, COLD, etc. lights), and I found one bad one and replaced it. All bulbs are now working.

The oil pressure sending unit is disconnected because a previous owner not only did not have it connected, but apparently, for reasons completely unknown to me, cut the wire way back where it joins the harness near the firewall. (Why would someone do this?) I only found the little stub of wire sticking out by accident. Anyway, I spliced another wire onto that stub and ran it over to the oil pressure sending unit, which is also new, but I have been reluctant to actually connect it because I'm not 100% sure that the little wire stub is actually for the oil pressure sensor. Again, how can I check this? If I ground that wire, should the OIL light go on? Should there be 12 volts present on that wire when the ignition is on?


In spite of all of the issues above, a lot of things do work.

The top goes up and down without a problem. The cigar lighters (one on the dash and one in each rear armrest) all have power and, after replacing the original, rusty units whose removal I asked about on here some weeks ago, now work. The power lead to the radio (the radio is currently out of the car) energizes when the key is on ACC or ON like it's supposed to. After replacing two bad bulbs, all four courtesy lights (two under the dash up front and two on the rear armrests) work. The light on the underside of the trunk lid that lights up when the headlights are on works fine. The similar light under the hood is disconnected, apparently by that same idiot who cut the oil pressure sensor wire, and I don't know where under the hood it is supposed to be connected.

Here's another observation/question related to the courtesy lights. As I said, all four light up when the doors are opened. But when I rotate the headlight switch to turn them on, only the two front ones go on. There is a switch on the dash right next to the power top switch that says "courtesy lights", and when I turn it on, only the two rear courtesy lights go on. Is all this correct? The two front ones with the headlight switch and the two rear ones with dash switch? Seems like an OK arrangement to me, but it would be great to verify that.

The turn signals, brake lights, parking lights, and headlights all work, although neither high-beam goes on when I hit the floor button. I don't know if they're burned out or if there is another issue, and I haven't had a chance to check. It's too bad if they're burned out as both high-beams are T3's while the two lo-beams are not. Given that they're T3s, they might very well be 42 years old and thus not work for that reason.

One last tiny question concerns the parking lights. When I pull the headlight switch out to the first stop, the parking lights and tail lights go on like they're supposed to. When I pull it out all the way, the headlights go on, but the parking lights go off and only go on if I use the turn signals. Is that right? I thought that the parking lights stay on when the headlights are on, but I really don't know. Otherwise, things seem fine with them.


Thanks for listening!