Headlamp Motor Problem?

[BrianZ]

I have a 1992 base model. After changing the spark plugs I reconnected the battery and noticed that the headlamp tilt motors ran for about 4 or 5 seconds. When I turn the headlights on or off they tilt and then the motors continue to run for about 4 or 5 seconds. I don't seem to remember it doing this before. Is this normal?

 

[ecss]

When you reconnected the battery, the headlight control module
drives the headlight buckets to the closed position. You probably
never noticed the motors continuing to run because the hood was
always closed. I'm assuming it was open when you noticed
the motors running?

You need to install 3 Delrin bushings in each motor.
They act as a clutch for the motor. From the factory from what
I've seen a gel was used for the clutch. The gel eventually
dries out and turns into a powder. Some people say bushings were used. Anyways the bushings are available from Corvette part places or any auto part store in the Help isle. The same bushings are used to repair older Ford power window motors.

Buy Dorman - Help Window Regulator Gear Plugs - Ford 2006-65 74410 at Advance Auto Parts

Here's a video where the person is replacing the driven gear but
he shows the bushing installation.

On one of the motors to reinstall the driven gear because of the
way the gear teeth are cut you need to loosen the three bolts holding the motor housing halfs together.

Don't completely remove the bolts because if the housing
seperates you will have to reset the brushes. When you
pull the housing apart that will give you enough clearance
to push the driven gear back into position. Some people file
the gear teeth down.

How to change the headlight motor gear in a C4 Corvette - YouTube

 

[vetteoz]

The gel eventually dries out and turns into a powder.

http://www.corvetteactioncenter.com...34889-1990-headlight-problem.html#post1128860

You need to install 3 Delrin bushings in each motor.

http://www.corvetteactioncenter.com...34889-1990-headlight-problem.html#post1128926

 

[BrianZ]

Doesn't the headlamp control module sense current? Wouldn't that be the first place to start? Delring bushings? Is that like muffler bearings or blinker fluid? Makes no sense to take apart the motors and modify them.

 

[ecss]

The headlight control module removes the voltage to the headlight
motors when it senses excessive current draw.

The motor shaft has a worm gear on it that drives a large
plastic toothed gear that drives the headlight bucket linkage.

Since your motors continue to run after the buckets hit the stop,
it indicates the driven gear is slipping. This causes the current
draw from the motor to be less than what is needed for the
control module to sense the bucket is at the mechanical stop.

The bushings act like a clutch and cushion the force so the gear teeth don't get damaged when the bucket comes to a stop or gets jammed by something.

 

[vetteoz]

Delring bushings? Is that like muffler bearings or blinker fluid?

:eyerole

People put up LINKS for you so you will LOOK at them and UNDERSTAND what you are being told
See
Corvette Headlight Repair Set, 1988-1996 - Corvette Parts And Accessories

Makes no sense to take apart the motors .

Your right , especially if the inside of your headlight motor gearbox looks like this

 

[BrianZ]

What I don't understand is why both headlamp motors did this at the exact same time. When I reconnect the battery they both run for a few seconds. Could that be like you said the gears are slipping and not creating enough current for the headlamp control module to shut them off? When I turn on the headlights they both rotate just fine. It seems the motors have the necessary power. If a gear was slipping I would think they would rotate slow and sluggish.

 

[lilbubba]

Need a permanent thread diagnosing and fixing the various issues that come up with c4 headlights

 

[roger longman]

Seems to be not neccessary, as apparently, some new members know better than our established and, knowledgable members......Roger..:eyerole

 

[vetteoz]

Need a permanent thread diagnosing and fixing the various issues that come up with c4 headlights

The common problems are well known and documented as shown by the links I put up in both current headlight threads..
Covers 99% of most problem
The OP may is this case have a unique or rare problem not seen before. Faults with the solid state controller used on the late motors are very rare
but even after 15 years of C4 ownership ,I am well prepared to accept "new" problems , especially given increasing age is now a factor on the orginal parts
now 20+ years old

 

[lilbubba]

U got a point i meant most common issues

 

[roger longman]

In this case, the OP originally stated, that the problem occurs, when the headlights are turned ON or OFF. He then, later changes the situation, saying it occurs only when they are turned OFF.....Roger.

 

[BrianZ]

One thing to note. The headlamp motor control module wasn't bolted in place like it should have been and has been bouncing around in there for who knows how long. I bought the car just over a year ago and have been finding a lot of things like this. I'm expertly skilled in electronics and this issue has me thinking. I might just develop a PLC controlled system to take care of this problem and with a bit of luck could sell it to people with the same issue. Or at least sell the plans and parts list. Considering both motors started doing this at the same time I have to believe the control module is bad. The headlamp motors run for about 4 to 5 seconds after they're already open or closed. So this tells me the module has a timer that times out if the required current to shut off the motors has not reached that level. Pretty easy system to duplicate. The only thing that may throw a wrench into my plans is that even turning on the parking light and turning them off the headlamp motors run the same way. To me that shouldn't happen. I'll have to look at the wiring diagram so more to confirm this.

 

[BrianZ]

In this case, the OP originally stated, that the problem occurs, when the headlights are turned ON or OFF. He then, later changes the situation, saying it occurs only when they are turned OFF.....Roger.

Roger, My original post states that the headlamp motors do the same thing when I turn them on or off. Read my later post and you will see that I don't specify that it only happens when they are turned off. Being critical of what people post here is not being of much help. Did you bother to ask me when you say I changed the situation? If not then the first post would be accurate. I never said in my post that it ONLY happens when they are turned off.

 

[roger longman]

Roger, My original post states that the headlamp motors do the same thing when I turn them on or off. Read my later post and you will see that I don't specify that it only happens when they are turned off. Being critical of what people post here is not being of much help. Did you bother to ask me when you say I changed the situation? If not then the first post would be accurate. I never said in my post that it ONLY happens when they are turned off.

Yesterday, you stated that, when you turn them on, they rotate just fine. I'm not bothering to ask you anything. As someone who is "expertly skilled", I would have thought you would know the importance of giving an accurate description of the symptoms, is neccessary, to get any chance of a correct diagnosis.

 

[ecss]

You're getting free advice on what could cause your problem.

Here's a thread that describes your problem.

Headlight module?? - Corvette Forum

If you substituted your name with adtbrown the
post would be identical even down to the Parking
light switch. :L

When you fix the problem, please post back what the fix was.

 

[KOPBET]

The bushings are cheap and the job is easy. Like has been mentioned, the old ones have turned to dust and need replaced.

 

[BrianZ]

You're getting free advice on what could cause your problem.

Here's a thread that describes your problem.

Headlight module?? - Corvette Forum

If you substituted your name with adtbrown the
post would be identical even down to the Parking
light switch. :L

When you fix the problem, please post back what the fix was.

Thanks for the info. I'm not trying to be a jerk or a pain in the ass. I just don't need people like Roger being over critical and not even offering any advice. I'll look into the bushings but I might just buy new or rebuilt motors. Not that I couldn't rebuild them, I just don't have the time to screw around with them. The money I have and I can get them at a local auto parts store for about $100 each. Then when I have time I will rebuild the old ones.

 

[KOPBET]

Thanks for the info. I'm not trying to be a jerk or a pain in the ass. I just don't need people like Roger being over critical and not even offering any advice. I'll look into the bushings but I might just buy new or rebuilt motors. Not that I couldn't rebuild them, I just don't have the time to screw around with them. The money I have and I can get them at a local auto parts store for about $100 each. Then when I have time I will rebuild the old ones.

Did you know you can replace the bushings in one motor in about the time it takes you to go to the local auto parts store and replace the motor (or less)? It's really that easy. $200 vs $10 and an hour of work is a no-brainer to me.

 

[gmjunkie]

Seems to be not neccessary, as apparently, some new members know better than our established and, knowledgable members......Roger..:eyerole

ding,Ding,DING.......................
Maybe that's the reason that some of the real "Goo Roo's" don't waist their time anymore!~!!!

Did you know you can replace the bushings in one motor in about the time it takes you to go to the local auto parts store and replace the motor (or less)? It's really that easy. $200 vs $10 and an hour of work is a no-brainer to me.

Speak for your self Kop,there are some here that have done this job so many times they can do both sides upside down,backward, while blindfolded!~!! :L