newbish question - popup headlight fuse?

[deathsled]

fudge, lol. Is there compatibility among the years? This is a 91 RT/TT I'm working on. Does my parts 92 base stealth have ETACS? I wonder if I can rob that one....

[RealMcCoy]

it depends on the part # of the ETACS in the N/A... Your RT/TT should have come with MB629054, which was replaced with MB852413. If your parts car has either of those part #s, it will work.

[deathsled]

Well I know what I'm trying tomorrow afternoon Thanks a ton!

[Steve '92ES]

Before you go too far try re-setting the ETACs by disconnecting the battery for a few minutes. Its kind of a long shot but they have been known to screw up from time to time, especially if the battery voltage gets low. If that's the problem a re-set should clear it right up. Its worth a try, anyway.
Your parts car probably has a different part number ETACs. What sets the ETACs apart isn't the year so much as the options that the car has. Unless your base stealth came with all the options including the security system, power windows/doors (my ES actually has hand crank windows..) pop-ups (a generational difference) rear window defogger, delayed headlight shut-off, or anything else I can't think of right now it will be different. I don't think it matters though. I'm pretty sure you can plug in any ETACs, it just won't run any of the stuff that donor car didn't have. At this point you probably don't care if the security system doesn't work if you can get the headlights going...

[Steve '92ES]

This seems like as good of a place as any to contribute something I wrote for some else about the pop-ups. This isn't specific to your problem but just a description of the system.

The easiest was to explain this is with a quick run down on how the pop-ups work.
Fist thing to realize is that the motor doesn't reverse to flip the lights up or down. The motor always runs in the same direction. If you applied power directly to the motor the lights would continually run up and down, up and down, up and down until you cut the power. The relay also doesn't change the direction, it just turns the motor on and off.
The whole trick is to shut the motor off when the light is in the position you want it in.
This is done with a switch built into the headlight assembly.
When you turn the lights on power is applied from the headlight switch to the "UP" input of the ETACS unit. the ETACS starts a 10 second timer and applies power to the "UP" side of the switch. If the lights are in the down position than the switch is in position to pass power on to the coil of the relay, which then turns on the motor. The motor runs until either A) the headlight reaches the "up" position, where the switch is flipped and the relay shuts off, or B) the ETACS timer expires meaning that there's ice jamming the headlight or there's a fat chick sitting on your hood.
When you shut the lights off power is applied from the headlight switch to the pop-up button switch. If the button switch is in the close position power is passed on to the "DOWN" input of the ETACS, the ETACS re-starts the 10 second timer and applies power to the "DOWN" side of the switch. If the lights are in the UP position than the switch is in position to pass power on to the coil of the relay, which then turns on the motor. The motor runs until either A) the headlight reaches the "down" position, where the switch is flipped, ready for another go in the other direction and the relay shuts off, or B) the ETACS timer expires meaning that the screwdriver you couldn't find rolled under the headlight or there's a fat chick sitting on your hood.
Remember that part about power going to the button when the lights are off?
If the headlights are on then the lights are up anyway so the switch has nothing to do.
If the lights are off than power is applied to the pop-up button as mentioned above. If the button is put into the "up" position at any time the headlights are off power is switched from the "DOWN" input of the ETACS to the "UP" input of the ETACS. If the headlights are already up when you push the button than the switch blocks the power from getting to the "DOWN" input of the ETACS, keeping the headlights up.

So, what can we tell from all this? Well, a couple of things. First, if the pop-ups work in one direction but not the other, say they go up but won't go down, its probably not a fuse. There's only on fuse ( fusible link #2 under the hood) that runs both lights in both directions. Its probably not a relay either. There's two relays, one for the right headlight and one for the left, but its the same relay and the same contacts for either side that runs the lights up or down.
This is why its important to check the operation in both directions. If the headlights won't go up use the manual knob on at least one headlight assembly to put it up, and see if it will go down under power. Conversely if the lights are stuck up, crank one of them down and see if it will go up under power.

If one of the headlights work but not the other you can probably rule out:
The fuse
The headlight switch (on the steering column)
The pop-up switch
The ETACs
All of these are common to BOTH sides. On the other hand if neither light works in either direction ALL those are suspect. If both lights work in one direction but not the other you can rule out the fuse but the others are still suspect.

So, it seems that the switch in the headlight assembly is pretty key to all this. Where is it and can it be adjusted? Can you bejigger it to get the "sleepy eye" look?
(nope) Ha! I brought pictures...
On the side of the bucket, by the motor, there's a round cover over the up/down switch assembly. Take out the two screws holding the cover on and pop her open. Inside the cover you'll see three brushes that ride around a copper disk. Make sure the brushes are making good contact to the disk and are not worn down or covered with gunk, the disk is covered with conductive grease but the brushes shouldn't be all black. You may have to pry the brushes down a bit GENTLY to make sure they connect firmly. Also inspect the disk, it should be solid all across the disk except for the two bumps on the inner and outer edges. Make sure the copper hasn't worn away in any of the "tracks" through the grease. IF it has you could try bending the brush to the side just a bit so that it takes a new "path" around the disk.

[deathsled]

so I did a little poking around in the fuse box under the dash this afternoon, I didn't have any extra fuses on hand, nothing looked blown, but I tried switching a few of the same rated ones around. I can now pop the headlights up and down using the button on the dash, but only if the headlight switch on the turn signal stalk is set to OFF. Once the headlights are turned on via the stalk they neither go up or down on using the button on the dash. At least for now I can pop up the lights and then turn them on. I did also find that my turn signals DO work, but only when the ignition is ON.

ETACS still looking like a possible culprit? I bet the one in my sohc is compatible, that car has all options except security.

[Incog]

Not trying to get derailed here -- but Steve's detailed explanation got me wondering... I've got one headlight that gets stuck up from time to time. Usually if I let it sit for 5-10 minutes and start the car again, it will go down fine. I assume its the headlight motor getting stuck on a flat spot. That sound like a good assumption?

[Steve '92ES]

Once the headlights are turned on via the stalk they neither go up or down on using the button on the dash.

Do they go down when you turn the lights off (with the stalk), or are they stuck up no matter what you do?

Usually if I let it sit for 5-10 minutes and start the car again, it will go down fine. I assume its the headlight motor getting stuck on a flat spot. That sound like a good assumption?

It could be that, or it could be a problem with the switch in the headlight assembly. Next time it gets stuck try turning the manual knob ever so slightly to see if moving it off the flat spot works. Remember there's a timer on the circuit. By the time you pop the hood and jump out of the car you'll have to cycle the lights on and off again to see if it worked.

[deathsled]

Do they go down when you turn the lights off (with the stalk), or are they stuck up no matter what you do?

It looks like they're stuck up no matter what I do. However, I do swear I saw them lower on their own yesterday when I cut the car off or opened the door or something, but I just tried to replicate it and they just stayed popped up.

It also just occurred to me that this car could have a snake eyes mod done to it already, however, the lights should still be able to come on with the ignition off....and the popup button should work whenever, not just when the headlights are OFF, lol

[Steve '92ES]

At this point it looks like they go up up not down... or an I getting all confused?
Try cranking one down manually and see what makes it go up.

I'm starting to think its either the headlight stalk switch or the pop-up button switch.