K.C.E.

1994 Coupe

When I turn on my headlights, the noise continues after the headlight are open and after they close.

I know this has been on the forum before....and there is a nice thread.....and the problem is common to C4 and the first step is probably replace the plastic gear......

My question is:

Using a Fluke meter (measure volts, amps, ohms) how can I troubleshoot the electronics in order to isolate the problem between the switch, control module, and broken gear?

Note: This noise happens using the parking lights only as well (i.e. the gear should NOT be moving). So I assume it is not a bad gear, but probably in the module or switch.

Thanks.

kc

John A. Marker

The gears usually are the last to go, it is the three bushings that usually fail.

QZRBLU

kc,
Just to add to John's post, you can source the nylon bushings
at just about any auto parts store that sells the HELP line of parts.
The bushings are sold as 'Window Regulator Gear Plug'

http://www.pepboys.com/product/details/9514261/00769

HTH,

Kmcoldcars

Buy 6 of the bushings and replace them in both headlights. The originals well be powder and small pieces. It is easy to replace them and will only take about 2 hours for both headlights, going slowly.
There is no need to get out a Fluke or do any other type of troubleshooting until the bushings are replaced. Then, if there are other problems, you can go after them.

TA

https://www.corvetteforum.com/forums...c-rollers.html

K.C.E.

Thx for replies......seems like doing the bushings first is a good decision.....I am still puzzled why I get a noise when engaging the parking lights only.....

shootnstarz

Hummm, not sure why the motors would run with just parking light. I'll check mine this morning.

BTW, if you go through the process of replacing the bushings I suggest also replacing the gear, since you're already there. I even replaced all the mechanical bushings in the pivot shaft and motor linkages when I did mine, only $30 for a teaspoon of tiny nylon bushings.

Rick

QZRBLU

[QUOTE=K.C.E.;1588918480]Thx for replies......seems like doing the bushings first is a good decision.....I am still puzzled why I get a noise when engaging the parking lights only.....[/QUOTE

KC,
It's possible that the overcurrent circuit has never seen a large enough load on the motors that it continues to attempt to close the headlamps when you switch the parking lights on. In your case I would probably raise the headlamps and disconnect the motor connectors. Leave them like that until you repair the pellets/rollers.

Mick

wzschirnt

Both of my c4's did the noisy headlight deal when the parking lights are turned off before I fixed the bushings and gears in the headlights. The headlights think they are still up and are trying to complete the 'close cycle'. When the headlight gears/bushings are broken, the headlight close cycle stops because the motors stop due to the 'overload or overheat' protection, not because it thinks the headlights are parked. Fix the headlights and the running noise will stop.
The signal for the headlight up function comes when the main lights are turned on, but the signal for the headlight down comes when all lights are turned off. If you just turn on the parking lights, no noise, but turn them off and the headlights try to retract. So you can leave the headlights up and off to clean, change bulbs, etc. Just went and tried this on my cars.

Fix the gears and all will be cool. Good luck.

Good luck.
walt z.

K.C.E.

Thanks for the input.

Good stuff.

fyi....in general comment....I belong to four different forums (We own 4 cars).....the other forums are rather weak when compared to this one......

shootnstarz

Ditto on the two other Corvette and the two 3rd Gen Camaro forums
I was on.

Rick