C2 Headlight Rotation Electrical Issue

[Roger P.]

A few months ago, I posted a problem that I was having with intermitent rotation of my headlight buckets. Typically, only one bucket will open & close slowly, while the other bucket stays closed. As I continue in my attempt to open the other bucket, the slow operating bucket will eventually get about halfway and then not move at all. If I start the car and wait a few minutes, the operating bucket will open & close again, and eventually, the inoperative bucket will begin working as well. At this point, they will not only both work, but will work at a proper "faster" pace (in about 3 seconds). Several members offered suggestions on how to diagnose the problem, as well as suggest items that may be the cause of the problem (from the motors, to the firewall connection, to the up-down switch). I am not a mechanic (however I am very handy and do quite a bit on my own), but my brother-in-law owns a low-voltage business and gave me a hand with this task. The "Cliff Notes" version of the story is that there is a voltage issue, not a mechanical issue with the motors. We have changed a few of the connectors at the motors, checked & cleaned the ground, and cleaned the firewall connection. I took apart the up-down switch and cleaned the "points" with fine-grit sandpaper. Nothing has worked, and he is still getting a "0" voltage reading when the one motor is inoperative. Does anyone have an idea what might be causing this challenging problem? My brother-in-law hasn't given up, but it looks like we are running out of ideas. It appears that the wiring harness in one continuous harness from the firewall to the lights, but I see that a few vendors sell a "headlight extension wiring harness" for C2's. Does my car have this harness, and might that be the source of the problem? If so, where is this extension harness located? Any ideas would be appreciated!

Thank you,
Roger Piper (50141)

[Jack P.]

Re: C2 Headlight Rotation Electrical Issue

A few months ago, I posted a problem that I was having with intermitent rotation of my headlight buckets. Typically, only one bucket will open & close slowly, while the other bucket stays closed. As I continue in my attempt to open the other bucket, the slow operating bucket will eventually get about halfway and then not move at all. If I start the car and wait a few minutes, the operating bucket will open & close again, and eventually, the inoperative bucket will begin working as well. At this point, they will not only both work, but will work at a proper "faster" pace (in about 3 seconds). Several members offered suggestions on how to diagnose the problem, as well as suggest items that may be the cause of the problem (from the motors, to the firewall connection, to the up-down switch). I am not a mechanic (however I am very handy and do quite a bit on my own), but my brother-in-law owns a low-voltage business and gave me a hand with this task. The "Cliff Notes" version of the story is that there is a voltage issue, not a mechanical issue with the motors. We have changed a few of the connectors at the motors, checked & cleaned the ground, and cleaned the firewall connection. I took apart the up-down switch and cleaned the "points" with fine-grit sandpaper. Nothing has worked, and he is still getting a "0" voltage reading when the one motor is inoperative. Does anyone have an idea what might be causing this challenging problem? My brother-in-law hasn't given up, but it looks like we are running out of ideas. It appears that the wiring harness in one continuous harness from the firewall to the lights, but I see that a few vendors sell a "headlight extension wiring harness" for C2's. Does my car have this harness, and might that be the source of the problem? If so, where is this extension harness located? Any ideas would be appreciated!

Thank you,
Roger Piper (50141)

Hi Roger,

I am not an expert, I am sure one of our fellow members will give a better explanation later, but,

The headlight extension wiring harness connects the headlight bulbs to the main harness. It plugs into the main harness just infront of rad support , left fender. The headlight motors are fed by the main harness from firewall.

The two (motors and headlights) are fed independently from firewall socket.

I had a similar problem with my motors ( I have a 66 convt, owned it since 1969) .. The problem may be the wiring in motors, old wires, bad contacts, I sent them out this year and had the electrical parts worked on. I had cleaned and replaced the gears and still had problems. The rebuild on the electric motors did the trick. The work great for the first time in 20 years.

If your wires and plugs are not broken or compromised, and there are not mechanical gear or bucket problems, then you have to look inside. Take motors to a local shop that rebuilds alternators and generators. ( If you can still find one, ask a local boat dealer where they get their starters rebuilt, and have them tested. You can test them by taking them out of car and running them with car battery. Neg to neg on motor ground screw, and postive to one of the two conectors on motor. Touch each one with postive lead, motor will run right or left depending on which terminal you touch.

Mine would run left but not right on one motor and fast and slow on the other motor.

Simple test. It is also good to just run the motor for a few miniutes in each direction to clean carbon off internals. They don't get a chance to run much in the car.

Jack

[Roger P.]

C2 Headlight Rotation Electrical Issue

Jack:
Thank you for your diagnostic suggestion, and for explaining the extension harness. Later this week, my brother-in-law and I will first try to test the motors with a direct power line from the battery (without removing them). If they work in both directions (up & down), then we will have to look even closer at the ground connection and the firewall connection. Last night, a friend mentioned that he had a similar problem and found the ground wire (separate from the harness) to be making poor contact. He fixed the ground and sprayed the firewall connection with a little CRC marine lubricant (which was recommended to him by a Corvette mechanic). He claims that they have been working flawlessly since the repair.
As always, I'm hoping for a simple fix .

Thanks again,
Roger Piper (50141)

[Wayne W.]

Re: C2 Headlight Rotation Electrical Issue

You need to start with the basics. The motors will not work correctly if the buckets are hard to turn. Check that first. Make sure the buckets turn full range without any resistance. Then look at the motors. It is common for them to be gummed up with old grease and bad gears. If they stick, they draw a bunch of current and get hot. The internal thermal switch opens and they stop all together. A possible scenario is that after you start the car and the alternator kicks in, you have higher voltage, which naturally will do a little better job of powering the motors. With the heat generated from your previous attempts the motors themselves are loosened up a bit, so they work better.

[Jack P.]

Re: C2 Headlight Rotation Electrical Issue

Rodger, as Wayne has indicated and I stated, you have to check mechanical items first. You do have to take out motors, one , to test buckets as indicated, two, to bench test motors as described. Be very careful with ground screws on motors. If they are not the right length, they can be screwed in too far and they will cause internal electrical damage to motor winding. If they have not been serviced in the past few years, they will need the old grease and dirt cleaned out.

It is not hard to take out motors, much easier if you remove hood, Just mark hinges so you can put it back in same spot. With you friend holding the hood, you can have it off in 3 minutes.

You will be glad you did it, when you see the gump that has accumulated over the years in the motors.

Jack

[Randy R.]

Re: C2 Headlight Rotation Electrical Issue

At what place are you reading 0 volts?

Randy

[Norm B.]

Re: C2 Headlight Rotation Electrical Issue

Don't totally discount the up/down switch yet. I was having similar problems on my 63. Both motors worked but one tended to be much slower than the other. When the car was running and the voltage was higher they worked much better but not as well as they should. It turned out that the clips that hold the back of the switch on were weak and when I tried to operate it the backing plate would push away from the contacts allowing some connection but not good solid contact. Almost impossible to discover this unless the switch is out of the car.

Try this quick test before you spend any more time and energy; disconnect the connector at the back of the switch and try to operate the motors by using a jumper wire on the connector itself. I used 14 guage solid wire from some scrap house wiring, works well. The center contact is the hot one and the other two are for open or close. If there is marked improvement then the switch is at least part of the problem, if nothing changes you have at least eliminated the switch as the culprit. It only takes a couple of minutes and is worth it to eliminate the switch as the source for once and for all.

[David D.]

Re: C2 Headlight Rotation Electrical Issue

You need to start with the basics. The motors will not work correctly if the buckets are hard to turn. Check that first. Make sure the buckets turn full range without any resistance. Then look at the motors. It is common for them to be gummed up with old grease and bad gears. If they stick, they draw a bunch of current and get hot. The internal thermal switch opens and they stop all together. A possible scenario is that after you start the car and the alternator kicks in, you have higher voltage, which naturally will do a little better job of powering the motors. With the heat generated from your previous attempts the motors themselves are loosened up a bit, so they work better.

Hey Roger,
I agree with Wayne about starting with the basics.....My friend had a similar problem and here is what we did, which narrowed it down. In his case we suspected (and found) a stuborn motor....

1. We removed the slow/stopped motor.
2. While motor out, check for free moving bucket.
3. If sticky - Repair, if free moving concentrate on motor
4. With motor in hand, we plugged it into the other motor connector
5. Ensure Ground connection is good , and as suggested, the correct length.
6. We ran the motor up and down several times
7. It worked (sort of) a couple times, but then appeared to get hot, and acted like it was partially shorted......
8. We replaced the armature and cleaned contacts etc....
9. His now works fine, lasts long time

Norm may have a good suggestion as well, but in our case, we simply eliminated the switch by installing mine. If you have a friend with a mid year close by, you can also try this.....
Bottomline, try to narrow down ...... It sounds so familiar to my friends problem, I suspect yours to also be a tempramental motor.
Good Luck,
David

[Harry S.]

Re: C2 Headlight Rotation Electrical Issue

The lower end of the armature rides in a bronze/brass bearing/bushing. If the bearing/bushing come out-of-round this will also cause the slow/stop problem. This was my problem. The part is available from LIC, but it's tough to replace without the right tools.

[Jack P.]

Re: C2 Headlight Rotation Electrical Issue

The lower end of the armature rides in a bronze/brass bearing/bushing. If the bearing/bushing come out-of-round this will also cause the slow/stop problem. This was my problem. The part is available from LIC, but it's tough to replace without the right tools.

Very, Very . Very tough to replace without right tools, we find that out the hard way.

Sometimes sending it out to be fixed works best

Jack

[David D.]

Re: C2 Headlight Rotation Electrical Issue

Very, Very . Very tough to replace without right tools, we find that out the hard way.

Sometimes sending it out to be fixed works best

Jack

Oh yea, I almost forgot (or tried to)....Part of our learning process as well. Had to find a local welder to spot tac retainer back in place. New bushing worked great however.
David

[William C.]

Re: C2 Headlight Rotation Electrical Issue

Remember too that the star washer on the ground circuit on the motor case goes between the terminal and the case, not between the bolt and the terminal.

[Roger P.]

Re: C2 Headlight Rotation Electrical Issue

Gentlemen:
Thank you all for your different ideas as to how I should trace and diagnose the problem with my headlights. I am away on vacation now, but will print your replies to my post when my brother-in-law and I get back on the job this weekend. I am still optimistic that it is an electrical issue since the motors both work very well -- just not all the time . Randy, the information about the "0" voltage reading was my mistake which I confirmed when I asked my bro-in-law. We are going to run each motor with a direct battery feed and see what happens, as well as check the switch and grounding once again. Although I don't want to remove the motors, we will remove them for bench testing if we can't find the problem after all the "easy" tests have been exhausted. From what I have been told, the motor R&R isn't too bad, but the bucket R&R is a major project. Keep in mind that when the motors are both working, they are "zipping" up & down simultaneously in about 3 seconds. Again, your ideas are always appreciated, and have proven very helpful in solving many other issues since I joined NCRS . I'll keep you all posted of what we uncover by the end of the weekend.

Thanks again,
Roger Piper (50141)

[Timothy B.]

Re: C2 Headlight Rotation Electrical Issue

Roger, Check the headlight harness ground at the core support and check that the core support is grounding good to the frame without corrosion.

[Francis F.]

Re: C2 Headlight Rotation Electrical Issue

Roger,
a good way to improve the ground connection,or any other
electrical conn.that I have found.Fill a small container w/
white VINAGAR allow the connector to soak in this liquid
for at least 1hr,then rinse w/clear water.The connector
should come out bright & shineeey.

I have used this method on my boat wiring harness
seems to do the trick,good luck.

Francis