'94 SC2 Coupe
 

Head light doors are not opening. I just discovered last night that the doors will not open. I just started trouble shooting today. There is a fuse for each door the fusees are good. And that is about it. The headlight switch at the moment is open for question as I am not sure exactly how much of it is working. With the doors closed it is hard to tell if the lights actually come on. The parking and tail lights do though.
I do not know at this time if there is a master fuse that controls power to the module that runs the motors or not. I have not found where the module lives or where the motors are how how to get after them.
I am sure I will figure that out later today but if anyone has anything that would add to help figure this out it would be appreciated.
Thanks.

Never mind, I found it. A corroded connection on a fuse in the IP fuse junction block. The electronics in these cars can have you chasing your tail.

Wrong again, I now have new updated information on how it does not work.
If I use the stalk on the steering column the head lights do not come on at all nor do the doors open. The parking lights and tail lights do come on.
However if you use the same stalk to flash high beams, something that can be done to signal passing conditions etc, the doors open and the high beams come on. The doors will stay open with the high beams on and the the head lights will time out and go out and the doors close.
So it seems that some signal or another is not being generate by that stalk to both turn on the lights normally and open the doors.
I am still open to suggestions and I am going back to research things.
Thanks.

Sounds like a short in the switch, unc. Since it operates on the flash mode, I think you can rule out faulty motors.

=========================
Yuh, I am beginning to think it is a problem with the switch after the latest go around.
That switch is part of the rotation of the stalk which means it is internal to the steering column and it does not look like an easy task to go after it.
I have been scanning the electrical diagrams that show how it it supposed to work looking for a fuse that might be blown that supplies power to the switch contacts.
The electrical diagrams are not the most easiest of lay out and of course the Chiltons/motor manual/haynes/mitchells format is not the most informative lay out anyway.
This is the point where a shop manual would be handy and I do not have one. Dunno, I just got up and am not functioning all that well. I'll get back to it some time today.
Thanks.

Well, if you start monkeying around with it, I'm sure you know to disconnect the battery first so the airbag capacitor can discharge and not blow out on you. That is presuming your model has an airbag. When did they become standard equipment?

The '93's had airbags, so I suspect his does too .........

I love this car. It more or less has been sitting unused for about a year in my driveway. I started getting it back to functional about Thanksgiving and it was recently I discovered the headlights were not functioning. So to day to exercise it a bit I drove it down to get the mail and surprise, the headlights magically fixed them selves. I suppose the contacts on the rotary switch that controls them had become oxidized and just using them a bit cleaned the oxidation off and things started working.
Good'O I can take that, magic works. Now I need to swap out and balance the rear tires with new Hankook's that came this week. The Goodyears finally dry rotted to the point where I am not going to use them. Too bad the tread depth was almost full and new. Damn the UV here hurts tires. Time to start sanding the body back down for another paint job, locate a gasket for the sun roof and see about swapping the dashboard instrument panel out with the one I bought here so the odometer will work again and call up Carvell and schedule having the seat re-upholstered. And check out the cam shaft that one of the members found to see if they are worth saving the money for and buying. That would liven things up a bit.
I just am not able to justify buying a new car despite the rational the Chevrolet sales manner tried to convince was valid. What was it? They don't make them any more.
Funny the concept that 1, I own it and 2 it is paid for never entered his lil'bitty mind.
And yuh, it has air bags and if I am going to spend money on this things I am going to opt for a new steering wheel. One with out air bags if for no other reason that the cover for them has gotten hard and crispy but a better one is, cosmetics. A new steering wheel with some looks to would brighten up my day and maybe even let me get the horn to work again.

Thanks
Uncljohn.

Heres a little logic for NOT buying a new car at this time that you might try bouncing off your chevrolet sales manager, powertrains in new vehicles are about to take a big leap in power output and fuel efficiency. The manufacturers have known for decades how, in theory anyway, to greatly improve the efficiency of the ICE (internal combustion engine).

Its a three pronged approach, of which the first two prongs have been implemented. Those are computer controls on the fuel/air mixture and the ignition timing. The third prong is valve control. Right now it is all mechanical, as it has been since the dawn of the automotive age, with a small amount of control recently with variable valve timing.

Nissan and BMW have experimented and gone as far as a limited production of engines where the cam rides on a second cam that basically changes the valve lash. At idle, only the very top of the lobe is used, as the throttle pedal is pressed, the cam begins to use more of its lobe. The throttle body is completely eliminated, the cam is the throttle.

Honda has addressed this with their V-tec engines, but that is basically just two fixed cam profiles.

Chrysler and Fiat are introducing their multi-air engines which use a master/slave cylinder between the cam and the intake valve instead of a rocker. The cam profile is a high output, high rpm cam, but a computer controlled solenoid opens a valve between the master and the slave cylinder, reducing the profile as needed for the operating conditions. The solenoid can open twice in each cycle so that it can trim duration off both the leading edge and the trailing edge of the cam profile. Initially the computer will only provide three profiles, but as this technology developes, they can have an infinite number of profiles.

One technology that is currently used in large industrial diesels is to have the valve directly actuated by a computer controlled solenoid. This would be the ultimate and all the manufacturers have been working on it. They say the hang up is getting a solenoid that would work throughout the whole range of a modern gas engine.

This eliminates the camshaft and its complicated and somewhat sensitive drive mechanisms. It would also allow a very high static compression ratio for the engine and then the valve duration and timing would control the dynamic compression ratio like the Miller cycle engine. It could even allow the engine to go into a diesel mode that uses gas instead of diesel fuel. Its very tricky to do with a mechanically controlled engine, but when it works, it gets great highway mileage.

Ultimately it could even allow the engine to operate in a 6 cycle mode for super cruise economy or even a 2 cycle mode for ultimate power. This all needs direct injection for the gas/diesel mode and the 2 cycle modes to work, and a turbo is also needed for the two cycle mode to work. You are seeing the groundwork here with the development of direct injection engines and turbocharging.

With the new CAFE requirements driving the industry to more efficient powertrains, I see this coming out in the near future and that is what I am holding out for.

A NASCAR MOTOR, something that is a push rod v8 will run reliably in the range of 10,000 rpm but have a life span of some where in range of 1000 miles is something that can be built using todays technologies for about $100,000. Is neither practical nor cost effective when reduced to practice in to days world and has little to no input into the modern motor other than a light weight oil to encourage some un-measurable in crease in CAFE standard fuel economy in the real world however has contributed almost 110% to increased oil consumption and reduced reliability which is not only measurable but is a plague that infects modern engines after XX number of miles to where the manufactures are considering but have yet to implement the non-servicable but throw away motors.
Where as F1 which runs at the cutting edge of the technology you are making an reference to has implemented motors that will run at twice the rpm and less fuel mileage and are sensitive to an increased loading of 20 gallons of fuel which will effect the performance measurably but also have increased the cost of these things a factor of 10+ while decreasing the reliability to next to nothing.
It sounds like a positive reason to wait for it. No thanks I am not going to hold my breath for it.
The cutting edge of technology is causing todays motors to bleed to death and I have no interest in waiting for one to show up in the show room floor powering some drap piece of iron with 4 doors and be another variation of the badge engineered choices offered by most but not all of the manufacturers, which are also disappearing as we write.
The writing on the wall is pointing at a high tech one car meets everyone's universal application. And creating a case that I should buy a new one because what I am driving isn't being made anymore? My fleet of cars that I not only own but cherish represent that. And other then my Chrysler which at the time is trying very hard to to represent something useful which is why I bought it, but also represent a company that is busy shooting itself in the foot. I have no plan to hold my breath until another variation of ill designed technology hits the road.
Todays Hybreds represent poor application of an age old technology that also can not be cost justified when purchasing one.
Run the numbers on the purchase + operating costs of the latest's hyteck and compare it to the same numbers on the non-hyteck variant and they do not justify the purchase. Leaving it to the individuals choice rather than a cost analysis. And my choice?
Not in my driveway!

Absolutely fascinating, Kieth...my mind is stretching a bit to try and wrap around your post...if I'm grasping the concept here, the only actual rotaing member would be the crankshaft? Everything else, including the water and oil pumps could be electronically controlled, no? And the valves would be controlled by electronically-fired solenoids...thereby negating the need for cam-shafts?
Could feasibly completely change the shape of our "engines" as we know them, the old "pancake" engine form could be making a huge comeback soon...think of the space-saving features here...not to mention the fuel-savings of having a multi-faceted engine that could go 6-stroke, 4-stroke or 2-stroke in a heartbeat would enable...
Not sure if my earning category would put me at the head of the line for the first vehicle sporting that motor, but damn, hopefully at some point!;)

back to the subject at hand, shall we?

With the understanding that the following is from a 1991-1993 chilton's wiring diagram for 93 coupes:

In the underhood junction block there should be 2 10A fuses one for LH DR and one for RH DR.

Trace these wires --they should go directly to the headlamp controller module you seek.

I'd list the colors of these wires but the ink has bled and I can't make them out.

Alternatively, trace the wires in and out of the door motors themselves -- the module connects to both ends (electrically speaking) of each motor

L side: Orange/Black stripe in, Dark Green/White Stripe out.
R Side: Orange in, Dark Brown out


Still digesting the overall wiring diagram which includes the headlamp switch to try to figure out how the circuit is designed

Thanks derf, I found those fuses and wires. I was looking to see if there was some form of a main fuse that supplied power to those two as it appeared odd that both doors failed to operate. I could not really see down under the fuse box and other parts on the fender wells unless I started removing parts. But then I discovered if I flashed the high beams as a road request then both doors opened and the lights came on which told me that those two fuses were probably good. And I did find a master fuse in what is called the instrument panel cluster fuse block,that is the one in the passenger side of the consul. The wiring diagrams showed it as supplying power to the two fuses one for each door.
Further investigation pointed at the rotory selector switch on the steering column for turning on the head lights and opening the doors. Or leaving the doors open with the head lights on and yesterday or so, when I went out to tackle this thing, the rotary swich suddenly started operating the head lights and doors correctly. And I have not had a failure yet. This is leading me to believe the switch contacts for the rotary switch had oxidized and two days of fiddling with the thing cleaned the oxidized contacts up as I have not had a failure yet.
NEXT? I have to mount two tires, balance them and put on the front, move the front to the rear and throw away a pair of dryrotted Goodyears with almost complete tread left on them. What a waste they were.
Thanks again.

I'm of the impression that the only power for the headlight doors comes through those fuses, which go directly to the main +12volt bus on the UHJB (constantly hot) ...

Where as that sounds logical, the service information I have indicated another fuse was also part of the story, as indicated it was on the Instrument panel fuse block located on the center consul.

But let me point out, that is a moot point at this point in time.
1. All fuses were good when checked. Not that there might not be some form of corrosion problem at a connector or in the fuse block itself that could aggravate the problem.
2. As pointed out by another poster on the subject of service documentation using alltrade (correct spelling? I had never heard of them) as a reference. Something less than a factory service manual stands the possibility of having errors.
As for my Saturn I do not have a factory manual. I have a Haynes which has proven to be a valuable purchase and cost effective for the price paid for it and also using both other open public service literature which is both affordable and also general knowledge thus prone to abbreviations, elimination of what might be considered superfluous information and generalization, errors and not keeping up with running changes is pretty much to be expected. The stuff on the whole is cost effective and generally about 20% of Factory prices on service literature.
The stuff comes under the heading of it is better than nothing. And I have a large collection of that.
I recently paid almost 100 dollars for a 1977 set of factory manuals for my 1976 AMC Hornet. Yes they are one year different but I also own all the trim panels to clone a 1977 AMX and the manuals are close enough between years to cover the 1976 car but also tells me how to install the 1977 trim panels.
Auto, Chilton, Haynes and Mitchel's all look as if the same company printed them using the same data base and the same service format.
The only difference seems to be the cover. While each of us have our favorite, I am reasonably sure that there is not a whit of difference between them.
And 3
The biggest problem that I see is not having anything at all rather than whether something is correct or not.
Although correct is nice, so is a pencil and I have a copious collection of notes in my most off used manuals.

And last but not least the problem seems to have been dirty contacts on the switch that is buried some where inside the steering column. While I probably can pull this steering wheel I would rather not. The plastic material for the air bag is brittle and I am afraid it would turn into plastic shreds if I tried to remove it and I have pulled enough columns apart in my life to have learned that nothing inside a steering wheel is easy to get to it and I would rather not if I did not have to. And as the problem seems to have magically gone away, actually pulling something apart just because I might find something is not a valid excuse at the moment to do it.