Alarm Issue

[markd79ta]

When I lock or unlock the car, the lights flip up and down and the motors run for about 3 or 4 seconds after they go down. What in the world? …any ideas? Can the alarm be disabled?

[Christopherrr]

Are your headlight motor gears stripped?

[markd79ta]

Not yet, but they will be if this continues. This is an electrical issue.

[Injuneer]

It could be the result of the motors not seating correctly, due to problems with the gears. Listen for a grinding noise when they move up and down.

Could also be a problem with low battery voltage. Mine would do strange things when the battery was dieing.

[markd79ta]

Just replaced the battery. This only happens when the doors are locked and unlocked...it has something to do with the alarm being enabled/disabled. It is rather annoying.

[axgrndr]

in my opinion these guys are right on with the headlight motor. i had exactly the same issue after i just bought my car. i thought mine was the door controller module or something with the alarm sys. the right head lamp door motor nylon gear was stripped. made a weird ginding/humming noise followed by a swish sound after flipping up and down and closing as you described. there is a fix to spin the gear around by disconnecting the linkage and rotating it by hand. is a one time fix. happens a second time you have to get a new motor. i think it was on this forum that i found a link to it. if its for the right door motor, i have one that i bought for my 02 not used and would be willing to part with if it will fit. i got it just in case. gm part# 12335998.

[axgrndr]

here ya go. i found a link. basically what i did for the free fix. metal gears would be an option too.

http://www.bfranker.badz28.com/headlightfix/index.htm

hope it helps.

[Joe 1320]

in my opinion these guys are right on with the headlight motor. i had exactly the same issue after i just bought my car. i thought mine was the door controller module or something with the alarm sys. the right head lamp door motor nylon gear was stripped. made a weird ginding/humming noise followed by a swish sound after flipping up and down and closing as you described. there is a fix to spin the gear around by disconnecting the linkage and rotating it by hand. is a one time fix. happens a second time you have to get a new motor. i think it was on this forum that i found a link to it. if its for the right door motor, i have one that i bought for my 02 not used and would be willing to part with if it will fit. i got it just in case. gm part# 12335998.

Same thing happened to mine. I believe you are right on the money with this one.

[markd79ta]

I have a hard time believing that a stripped gear happened to both headlights at the same exact time, and the only time there is an issue is when I engage/disengage the alarm. There is no problems if I turn on the headlights. The headlights actuate as they should. If a stripped gear can cause this behavior I am astounded at the engineering behind this. Additionally, in the 12 years I have owned this car, never once did the lights pop up and down when I turned on/off the alarm...only when this problem started...it seems to me that a signal is being sent to the relay to engage the motor when a signal is not necessary. Also, there is no grinding when the lights go up and down. The motor just keeps trying to turn the light motors after both are already down...the noise is that of an electric motor being held in place under load. If the gear was stripped, it seems as though the same symptoms would occur by turning on/off the headlights. I don't know, but this all seems strange to me.

When I owned my '85 Vette, one light did not work correctly...sometimes up, sometimes down, sometimes somewhere in between. Everybody was convinced it was the gear and I needed a new motor. In order to troubleshoot and save some money, I wired the light to the relay of the light that worked, and the failing light worked correctly after that.

I guess I will try to track this down and change the gears if that is needed. Although, this seems pretty bizarre if the issue is in fact mechanical.

[Joe 1320]

I have a hard time believing that a stripped gear happened to both headlights at the same exact time, and the only time there is an issue is when I engage/disengage the alarm. There is no problems if I turn on the headlights. The headlights actuate as they should. If a stripped gear can cause this behavior I am astounded at the engineering behind this. Additionally, in the 12 years I have owned this car, never once did the lights pop up and down when I turned on/off the alarm...only when this problem started...it seems to me that a signal is being sent to the relay to engage the motor when a signal is not necessary. Also, there is no grinding when the lights go up and down. The motor just keeps trying to turn the light motors after both are already down...the noise is that of an electric motor being held in place under load. If the gear was stripped, it seems as though the same symptoms would occur by turning on/off the headlights. I don't know, but this all seems strange to me.

When I owned my '85 Vette, one light did not work correctly...sometimes up, sometimes down, sometimes somewhere in between. Everybody was convinced it was the gear and I needed a new motor. In order to troubleshoot and save some money, I wired the light to the relay of the light that worked, and the failing light worked correctly after that.

I guess I will try to track this down and change the gears if that is needed. Although, this seems pretty bizarre if the issue is in fact mechanical.

Brother..... I thought people were nuts when it was suggested to me. I laughed it off and not long afterward, the gear in the headlight fully stripped. As soon as the gears were replaced, the phantom headlights quit acting up and they started working normallly.

The headlight motor circuit needs to see an increase in load in order to shut off the power to the motors. When they do stop due to becomming fully open or closed, the load against the gears increases and the circuit is deactivated. If the gears are worn, as soon power is cut there becomes a slack in the gears. When you arm or disarm the alarm, it sees that there is no load against the gears and momentarily operates the headlights again. The open, then close and the power is again cut. Then the cycle begins again.

To me, the circuit design is goofy.... but I'm not an electrical engineer. Just don't be suprised if your headlight gear fully strips if you don't fix it soon.

[97Bandit]

not to be a smart one, but just gona say your headlights always go up at the same time... so it may not be so bizarre is they both go out at the same time due to the equal wear on the gears...

[Tweekd]

My driver side does the same thing.. Before I turn the headlights off ,I disconnect the motor , turn the headlights off , them manually crank it down & plug back in . THe motor is shot & I've tried gear rotation trick, but now both sides or the gear are shot .. lol On a side note , where besides the dealer , can you get a new motor assy..?

[Injuneer]

You can buy new metal gears from Brent Franker. Also has the "fix" for disconnecting the linkage to rotate the gear to the unused side, for those whoo haven't tried it yet.

http://www.bfranker.badz28.com/headlightfix/index.htm