What causes occasional headlight motor probs?

[Steve92LT1]

My 92 has a slight problem. Recently I've been having a problem with the driver side headlight not working. It would do it sometimes before but if I turned them off and back on, it would pop up.

Now, when it doesnt work, I seem to have to pop the hood and manually crank it up. THen it will seem to work normally for awhile. When I turn the knob, it seems normal, not tight or anything?

Is this a motor problem? Or a gearbox? I havent dealt with this issue before

Any input would be greatly appreciated.
Thanks
Steve

 

[vigman]

Peek A BOO! ( headlight motors )

Watch the following

Pop the hood.... at the base of the headlight motor.. there is a knob, have an assistant turn on the lights.... watch the knob to see if it spins.


Now have em turn the lights off..( watch & listen to the BAD side)
did the knob spin? ( If yes... you need new gear bushings)

If no... spin the knob manually.. be careful the knob MIGHT take off and now start spinning... ( if yes, the motor needs a rebuild )


Let us know!

In the meantime...unplug the harness on the offending light and leave it in the UP position.

Vig!

 

[vigman]

Further Info ( headlights )

The Three Nylon Bushings

In the final drive gear there are 3 nylon bushings which act as a shock asorber when the motor locks one way or the other.The control circut is a current sensing device.

When the Nylon bushings age ( read turn into cane sugar ) they jam up the works causing one of 2 conditions.

1) The Coarse Grind

The headlight will start to flip then JAM the bucket motor & reverse rotation so you get the Spastic bucket effect.

2) The Fine grind
The headlight will flip SLOWLY or start but not complete the flip but the motor will continue to turn in the correct direction untill it times out.

Mike

BTW look in the Mid America catalog for a nice pix

 

[Steve92LT1]

Thanks man.... I'll check it out in the AM and post back with my results...

Steve

 

[Steve92LT1]

The knob didn't spin so I guess the motor is bad... this really sucks.

Can the motor be cleaned internally... I'm good at stuff like this... are there any options besides a new one?

THanks
Steve

 

[Interceptor430]

I had a headlight problem on my '91 recently....
I checked the headlight motor by unplugging it from the
harness (a two wire connector), and put power directly to the headlight motor from an alternate (battery pack) power source.
My motor raised...then I swapped the polarity at that same plug, and the motor lowered....so, with the motor tested as 'ok'.
My shop manual then directed me to a series of checks with a test light at the HCM....it was bad....TLD had the best price for this, and it installs in just minutes....my lights work fine again.
the HCM (I think that's what it is called) headlight control module...it was located on the front side of the left wheel well housing has 2 wire plugs.
I hope this info helps you.

 

[vigman]

I agree with Interceptor

Try that first

Vig~

 

[Steve92LT1]

Well.. I decided to disassemble the motor completely. I cleaned up the brushes and commutator. They had a typical tarnish on them and the connection probably wasn't good. I cleaned it up well with some very fine grit sand paper, they will make a good connection now. I cleaned out the rest of the crap out of the inside of the motor housing. The was some junk in there. The windings and all look good. I put everything back together and it works and seems MUCH smoother when I crank it manually, so maybe it was binding in the motor . Now is the true test... to wait and see how it all works the next few days and if it acts up again.

Suprisingly enough, the insides of these headlight motors are very simple and not complicated.

Thanks for the info about the control module, if this doesnt work then I will check that next.

Steve

 

[Interceptor430]

Yea, just put some power to that boy and see if he moves.

At first, my left headlight wouldn't raise, other times it would.
The motor was fine...but I replaced the 3 little bushings inside there just for grins.... a couple days later the right motor started
acting goofy too.....did the same deal on that one...
then they both quit working.....what fun that was...but I was glad both motors were ok....and the headlight control module wasn't
that bad...$120, I think - which is cheap compared to the cost of
2 motors...

Best wishes with it.....keep us posted.

 

[Steve92LT1]

It's not the module.. it's the motor. I tried powering the motor with direct 12v and the same problem. It doesnt seem to have the power for the initial kick. If you spin motor, just a little bit then it will go up normally. It's like you have to jump it. I don't know what the best option is.

Steve

 

[Interceptor430]

Uh, did you try putting power to the headlight motor both ways?
Swapped the leads from your power source to the 2 wire plug?

If I remember right, there are only 2 wires that run to the motor.
Power to one wire/one side makes the motor run so the headlight will raise - then power to the other wire/other side makes the motor run the opposite direction.


:confused

 

[Steve92LT1]

yeah... thats what I did... there are only 2 wires

 

[Interceptor430]

OK....just wanted to ask - there was a 50-50 chance that maybe
the motor would work if the leads were swapped.
I hope you can get it fixed/rebuilt/etc and it's easy on the wallet.
:cry

 

[vigman]

Sounds like

New armature needed with brushes...

Vig~