Vehicle:
1999 Coupe, 68,201 miles

Problem:
Headlights intermittently not rotating open when activated.

History:
Problem began last month during a one week stay on Vancouver (lots of moisture). We didn't hit any hard rain, but I ran with the fog lights "on" (first click on the headlight switch stalk) while driving for most of that week. Last day on the island, we ran into a situation where I decided to turn the headlights on and when I rotated the switch fully ..NO HEADLIGHTS! The lights came "on", they just didn't rotate "open". Repeated attempts met with negative results.

Later than same day when we stopped for lunch, and afterwards when we came out I decided to try it one more time and BINGO...they popped open.

My first thought was all the "moisture" may have caused the problem, as we live in So. Cal. when there is no moisture! We never had anymore incidents during the rest of the trip home.

Last night, leaving a friends house, I hit the headlights and ...NO LIGHTS! Switched it off and back on and it worked...

ANY ideas of what's going on and a possible cure???

Thanks in advance...

 

 

mine is doing the exact same thing...i sometimes have to try to turn them on 4 or 5 times before they will open....i will be watching this thread....

 

When you select the lights is there a grinding noise? Does the motor activate and the headlights not move?

 

No noise what-so-ever from the headlight motors; the lights do come on.



I read Bill Curlee's expert thread (IMPORTANT ELECTRICAL INFO.) a couple months ago and I've been wondering if this could be a "ground connector issue"?

 

 

One time my left headlight didn't come up tried it again and it was OK. This is on an 02 with 14k miles on it, hasn't happened since. Sometimes things just happen on these cars. I've had some weird problems, cleared the codes and they haven't come back. Check it out.

Rick

 

I win the prize..........I think I stumped the group with this question!!!!

 

Could also be the headlamp module. One side would work intermittently, replaced the module, no problems since.

 

I just drove 150+ miles through the mountains yesterday with only the right headlight working. Initially, just before dusk, neither headlight door would pop open while I was driving on a trip from San Diego to Northern Nevada. After a few attempts to get the lights working, by turning the turn signal stalk switch on and off, the right headlight door opened and that light worked fine on both high and low beams. Since I had to drive another 150 miles at night to my destination, I did not try cycling the switch any more out of concern that the right door would not re-open.

Once I arrived at my destination, I turned the car off and then turned the ignition back on a couple of times. Each time I tried turning the headlights on. Each time only the right door and light operating correctly; the left door remained closed.

An hour later, I hopped back in the car to run an errand. This time, both doors and lights operated correctly. About 6 months ago, I had a short term problem with the left headlight door not opening, but cycling the headlight switch a couple of times solved the problem.

Has anyone had a similar experience? What was the problem/solution? It doesn't seem likely that both headlight modules have become intermittent, but maybe that is the case. My car is a late 2004, with about 13,000 miles on it. The car has not been rained on or driven on wet streets in about 7 months (SoCal), so I don't think moisture in some connector could be the culprit.

Edit: Looking a little further for general electrical problems, I ran across this thread:
http://forums.corvetteforum.com/show....php?t=1517493

Basically, it says that many intermittent electrical problems can be traced to faulty ground connections for that affected circuit. I don't have a shop manual, but from one of the thread illustrations, it looks like the left headlight has its own ground connection to the frame below the left headlight assembly. I will check that ground connnector out for corrosion tomorrow and report back to the forum.

 

The headlight motor ground is common for both headlights. It's provided by the headlight control module and the ground point is on the frame rail behind the passenger headlight. Check that ground to make sure it's not corroded and it ohms out properly.

The other simple possible solution is to spray some white lithium grease between the manual motor **** and the motor housing. I had a similar issue and after noticing that the motor would spin so tight upon closing that the manual **** would be wedged against the motor and prevent the headlight control module from opening the light. The headlight control module apparently senses when the motor arm hits a stop due to increased current and shuts power to the motor. If the **** is clamped tight the current may trigger the control module to shut power before it can start to open. One way to confirm this is when the problem happens simply turn the manual **** one or two turns to release the tension and try the switch again. I'll bet it opens.

Try this and let us know if it works.

 

JC,

Thanks for the suggestions. Naturally, both lights/doors are working just fine right now.

I think your intermittent "overtight/over-current" theory is a good one. I will try manually backing off the **** the next time I have a problem with one or both sides. I just checked both ***** and there is no binding at the present time. Each **** can be rotated about 1/2-1 turn clockwise before there is any resistance or binding.

I will also check out the resistance to ground for each side after I get a shop manual or a good circuit diagram that shows which wire color code goes to the common ground.

Anyone want to sell a used factory shop manual for a 2004 model?

 

I have had several cars with the same issue that was resolved by tighting the battery cables, The headlamp module is very voltage/ground path sensative. Its worth a try.

 

KP,

Thanks for your suggestion.

I just went out and checked the nuts on the battery cable. Both nuts were on quite tightly, so I backed each nut off 1/2 turn and then retightened them. We'll see what happens over the long term. I went problem free for six months the last time (and didn't touch anything)...

Steve

 

JC, I have this problem and when I loosen the ****, it works all the time. I have sprayed several times with white lithium grase and it doesn't make a difference. How much grease did you use? Can a stop be adjusted?

 

I didn't need to use a lot, but had to make sure it was well into the center of the **** where it meets the housing. Is it tight when you manually loosen it? With the grease mine was very smooth when I checked it manually.

Adjusting a stop may not make that much of a difference, but look at the close stop and you can try turning it 180 degrees to a fresh surface - that may have a small effect.

 

Well, I took off the battery terminals and cleaned them (wire brush and acid neutralizer). They did not seem very dirty or corroded.

Now, the headlights work 100 % of the time !