Some info on the 84-86 headlight system and why it does not always work right
Thru the years I have been asked like thousands of times basically the same question: My 84-86 headlight lift system does not work the way they should. How do I fix them?
The simple answer is there is no simple answer. If one or both headlights do not come up when turned on but might if you spin the knob slightly or does not go down for that same reason there is generally no single thing you can fix or replace to make them work like new again. The biggest single problem IMO is low voltage to the armatures. Thru the years every connection (especially the grounds) get corroded which reduces the flow of electricity to the armatures in the headlight motors. This is a common problem on any older car. Start at the battery and work thru the electrical system cleaning everything you can and regreasing everything. Even the headlight switch can be opened up, cleaned, regreased and put back together.
The headlight motor has to have enough strength to fully open the contacts when in the full up and full down position.
The relays on the headlight buckets are low cost and still available. You can replace them. I have a reproduction isolation relay the eliminates the plug insuring 100% perfect connections.
If you have not opened the headlight motors you should do that. In most cases you will want to replace the gear and bumpers right away. When new these headlight motors had grease in them. Over time that grease dries up and turns into a clay like material. Clean everything and regrease it. Hi temp grease is the best grease because it is slow to dry up.
There is one wire on the brush/contact assembly that can be soldered to the arm making a better connection. If a brush has fallen off or is worn to nothing I have new brushes and the correct glue to glue them to the arms.
Clean the battery cables (both ends). Make sure the small ground wire is intact and working well.
I've seen many times where a crimped on terminal end is corroded under the crimp. The only fix is to cut it off and install a new crimped on eyelet. You may have to sand the wires as sometimes the corrosion makes it way back up under the plastic insulation. It is best to then solder the crimped end on to the wire.
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PS: Everyone thru the years has wondered why that bimetal switch bulb is in these headlight motors. If the contact does not open and stay open the armature stays energized and gets hot. The bimetal switch will keep opening and closing until the battery is 100% dead. Why? Becuse there is a chance the armature might get so hot it could cause a fire. Pulsing it keeps the headlight motor cooler.
IMPORTANT NOTE:
I used to make an upgrade wiring/relay kit. I used standard relays one uses on the headlight buckets that you buy at any autoparts store, online etc. The last time I ordered like 50 relays to make these kits and over half were made in China relays. I did all the work to make them up for my kits only to find about 40% of the China relays did not work right out of the box. So I stopped making these upgrade kits.
This is going to be a real problem in the future. If you buy a China relay how do you know if it is good or faulty. Someday in the future I'll look at making up these relays on a circuit board and potted.
Some tips from Stan Miller who has rebuild many of these motors.:
1. When opening up the motor be sure to mark or note the orientation of the field coil (this is the part with the magnets). It can only be installed in two positions. If you flip it 180 degrees the motor will run backwards. The glob of white sealant is always facing the smaller case half. Sometimes it sticks to the case so noting this may not always help.
2. Do not mess with the original orientation of the large C-clips holding in the field coil magnets. If you press them in all the way they will interfere with the stator core on the armature when the armature moves down to activate the limit switch. This can cause the motor to jam up or prevent activation of the limit switch. Should be 1/8"-3/16" gap.
3. It is a good idea to polish the two contact points on the limit switch. I have seen these become fouled with carbon to the point where there is a constant or intermittent loss of conductivity. The limit switch itself is fairly easy to pop out of the assembly with a small flat screwdriver but can be cleaned without removal with a small piece of very fine emery cloth.
4. The next thing is to check where the glass tube breaker is soldered to the brush finger. If the solder joint has failed it must be cleaned and re soldered (even if still attached with the tab) or you will have a intermittent loss of power. This is a very common problem as I would estimate that I re-solder at least a third to half of all the motors that I rebuild.
5. One of the most frustrating problems with these motors is the infamous "click of death" situation where the motor doesn't have enough power to trip the limit switch either in the open or closed positions. When this happens the motors internal bulb reset breaker continually kicks on and off until it has completely drained your battery. If this goes on long enough it can damage the motor.
I have found that the most common cause of this problem is drag on the armature caused by a small amount of friction created by the spring when there is no end-play in the armature.
How to test: Install the armature assembly only into the case and then spin the knob to check for end-play and drag when rotating. It should spin freely with little to no drag while turning the knob. There should be a small amount of end play of at least a 1/32" to prevent this drag on the armature as it rotates. If you feel drag and no endplay then this is remedied by thinning the two black friction washers on each side of the limit switch trigger fingers. I am guessing these black friction washers must have expanded or thickened over time for some unknown reason. Maybe contamination by the grease??
6. A myth I would like to put to bed is that Firebird motors are exactly the same as Fiero motors. They are not!! They have a much weaker gear set and the spring on the armature is weaker because Firebirds do not have to push open a spring loaded headlight door like the Fiero motors do. Installing a Firebird motor into a Fiero is a short term solution because the weaker gear set will fail quickly.
