What exactly operates the headlight motor limit switch. On my '92, the gears stripped in the motors because even after the lights hit full up or full down, the motors continue to run. Somebody please help!!

 

i think the limiters are internal insite the motor assembly

 

Then what could be causing that and what exactly does the body control module do?

 

Headlight motors used on 92's do not have a "limit switch". Headlight door module monitors current flow through the motors and when there is a big rise in current draw, the module knows that the headlights are at the end of their travel range.

Thirdgen f-bodies do not have a "body control module".

 

The headlight doors module is bad, replace it.
The module is like a computer, it can't be repaired, it controls the up/down function of the headlights, it also senses whether to go up or down and when to shut of the motors.

 

You are getting good and bad advice here. First, the bad: The 1982-86 headlight units DO use relays and a control module. These units used two nylon gears inside. Now for the good: Your 1987-92 headlight motor unit doesn't have limit switches, relay or control module, but relies on load sensing to shut down when it reaches the end of the stroke. The 1987-92 headlight motor assembly was a vast improvement over the previous two-gear unit GM used. This unit has a large nylon gear that is driven by the worm gear on the motor shaft. The problem you describe is caused by two thngs, but both involve the large nylon gear inside it. First the nylon gear can strip. On Fiero & Firebirds you can remove the gear, turn it to a fresh part or the gear and reistall. When you remove the gear you will discover what I believe your real problem is. The gear has (or had) 3 cylindrical shaped solid gel inserts that transfer the load from the gear to a 3-lobe hub on the actuator shaft. These inserts harden and crumble with age. When they have broken down to roughly a spoonful of crumbs (as yours has) the gear will no longer turn the hub to raise and lower the headlight assembly. Instead hub will just free wheel on the gear. Several compaines (including mine) sell a headlight repair kit consisting of 3 precision machined, close tolerance Delrin bushings that replace the gel inserts and restore the headlights to proper function. I have two versions of the kit. TDS 207280 kit ($5) has the 3 Delrin bushigns and new screws and nuts to mount the motor housing (these often break on removal). TDS 208280 kit ($9.50) also includes the side cover and motor housing gaskets. Both kits come with a 4-page detailed and illustrated instruction sheet. One kit repairs one headlight. With every 2 kits odrdered I include a free tube of the Permatex WL-9 white lithium grease I recommend to lube the gear and bushings. Here is a picture of the 207280 kit.


E-mail me at topdownsolutions@yahoo.com to order a kit or get a price list.

Lon Salgren
Top-Down Solutions

 

Thank you for the info. However;, I rebuilt one of the motors just to test and it raises up and down correctly but still continues to run after it's at full up and full down. It was a temporary fix until I can find out why the motors won't stop. It'd be pointless to rebuild completely while I have this problem. Any suggestions on what is causing the "voltage" problem? Once again, thanx.:hail:

 

When you say you "rebuilt" it, what did you do? If you didn't replace the gel inserts you'll still have the problem. The motor will continue to run because the gear is free-wheeling on the hub/actuator shaft. If the motor doesn't sense the load from hitting the end of travel it won't shut off. If the unit was rebuilt and still you have a problem with is sensing, look at the solid-state unit that controls the motor. Sorry, I don't have a Firebird Manual yet to help any further than that.

Lon