84 headlight motor (Page 1/1)
Nickoman JUN 02, 10:35 AM
So, I did a juvenile thing, I saw a fellow fiero on the road and raised my lights ( to blink ) after shutting the car off I heard a motor running under the hood. The motor is stuck spinning...... I can raise and lower the light with the switch still, but it never stops spinning. Anyone had this problem in an 84-86 headlight assembly. Im gonna start by swapping relays to see if it follows the relay. If not. do the motors have internal limit switches?
theogre JUN 02, 11:15 AM
Motor spinning = motor is bad.
Like Gear(s) teeth broke.

Replacing relays etc won't help you.

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Dennis LaGrua JUN 02, 11:38 AM
Time to take that motor apart and rebuild it. All parts are available from the Fiero Store and from Rodney Dickman. Metal Gears, dowel inserts and even new motor brushes are all available. Much of the time you only need to replace the dowel pins but I just did one where the brushes were gone. Its not a difficult rebuild job but close attention must be paid to reassemble it in the exact same sequence as it was taken apart. If you don't wish to tackle the job, Fierofool on ths forum offers a rebuilding service

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Nickoman JUN 02, 12:00 PM
Thanks guys I'm gonna take it apart after work today. I believe you when you say its a bad motor,but for some reason I cant rationalize why it would go up and down with no issues, but just not stop. I'm much more mechanically inclined than I am electrically. Once I pull it apart im sure I will understand why.
fierofool JUN 02, 01:52 PM
If you don't know to do so already, unplug the single wire connector to the motor to stop the motor and save your battery.

There are a few things you must pay close attention to. The little short lift arm can be difficult to remove. Using an 11mm open-end wrench, loosen the nut until it's level with the top end of the threaded shaft. Hold the shaft with a pair of slip-joint pliers and while suspending the motor in that manner, strike the nut with a hammer until the lift arm comes into contact with the backside of the nut. The nut prevents damaging the threads on the shaft.

When you first remove the small half of the case, mark the motor stator windings on the shiny metal portion facing you so you know the correct orientation when you replace it. Then when reassembling the case halves, be sure the rubber D seal at the top of the case halves is seated in its place "Inside" the case halves and not captured between the top of the case and the knob.


Metal gears using bump stops are best. Gears without bump stops put undue stress on other motor parts and will require a teardown later to replace a part that you can only get from another motor. You must also brad the bump stop and gear retainer plate to the shaft or it will eventually come off. That's the plate with the 4 metal fingers.

If your replacement gear doesn't come with lube, purchase a tube of Permatex Ceramic Extreme brake lube. Part number 20354. It's synthetic and won't harm plastic gears or rubber bump stops. It won't be wasted since it's one of the best lubes you can use on your disk brake slider pins.
fierofool JUN 02, 02:06 PM

quote
Originally posted by Nickoman:

Thanks guys I'm gonna take it apart after work today. I believe you when you say its a bad motor,but for some reason I cant rationalize why it would go up and down with no issues, but just not stop. I'm much more mechanically inclined than I am electrically. Once I pull it apart im sure I will understand why.



The motor stops at the same place on the lifting gear inside. The motor doesn't make a full 360* rotation so you can have a run-on condition in one direction and not the other. The system works by running into a brick wall, so to speak. When the assembly reaches it's maximum up or down and locks up on itself, the internals of the motor moves up or down, exerting all the torque on the same 3 or 4 plastic gear teeth, each time. Most of the time it's the teeth on the upstroke that sheer off because there is more pressure from the weight of the headlight assembly and the headlight door springs fighting back. Then when the lights are turned off, the resulting weight and door pressure cause the motor to grab good teeth to go down. As it locks up at the end of the downward travel, it doesn't have the extra resistance as on the upward travel.

If you want me to rebuild the motor, you can ship the motor and dropship the gear kit to me. I charge $30 labor plus return shipping without markup. I guarantee my work for 1 year.
Nickoman JUN 02, 02:39 PM

quote
Originally posted by fierofool:

If you don't know to do so already, unplug the single wire connector to the motor to stop the motor and save your battery.




Was way ahead of you haha I unplugged it and put it down manually.
Thank you for offering to do the work, your prices are more than fair but Ill take a crack at it. I believe I have 2 spare headlight assemblies in the loft of my garage from the previous owner. Im gonna try to plug and play one, if it needs a rebuild ill rebuild the spare and pop it on. Thank you!
Nickoman JUN 02, 07:20 PM


You guys were dead right! after pulling it apart I see why it wouldn't trip the limit switch. it would free spin once reaching the top and never drew the motor shaft up or down to trip the switch.