Sunroof noise and movement

[guruerror]

Let me start by saying...this sound is NOT being caused by loose A-pillar trim. That's all taken care of...lol.

While driving at highway speeds (65+) with the sunroof closed there is a definite rattle and the glass can noticeably be seen to move up and down. Putting upward pressure on the glass with my hand reduces both the noise and the movement. It seems to me that the support mechanism which is designed to keep the glass in place is not as ridged as it needs to be to compensate for outside air pressure when at speed.

The severity of both the sound and the movement also seems to be impacted by which other windows are down. If only the rear window is down the problem becomes more pronounced. If any of the side windows are down the problem seems to lessen. I assume this is due to the change of the interior air pressure and flow which either helps or hinders the problem.

I've found a few (very few) articles on other forums about this and both indicated that the window motor needed replaced. The motor (PN 15781626) can be had for $330, but I wanted to throw this out there first and see if anyone has come up with another solution...or if someone has actually replaced the motor themselves, and what their experience was.

I had the same issue on my SUV, but it was much less pronounced...and I just sorta ignored it. It's a little more 'noticeable' on the SUT, so I'm gonna start looking into a solution.

Thoughts?

[guruerror]

The best I can tell when the sunroof 'thinks' it's fully seated in the closed position it's actually about an 1/8 of an inch into the vent position. Not enough to be visibly noticeable from the interior or exterior (or allow any leaks), but just enough to lift the hinges toward the rear of the glass out of the position where they have proper support.

From this position (where it 'thinks' it's closed) I can easily move the glass up and down by applying pressure; hence the bounce or vibration that I'm seeing as the wind buffets over the roof when at speed. As the glass moves I can actually see the hinge move too as if it has no support or isn't in a firm, locked position.

If I quickly tap the Open side of the sunroof control...lowering the rear of the glass a fraction of an inch...the glass becomes very sturdy. When in this position there is almost no movement when applying pressure and the hinge doesn't move at all.

I'm going to give it a test run Sat on the interstate to be certain I'm on the right track. If that fixes the issue I'll either need to figure out the "Initialization/Teach Process" for the H2 or find a way to manually adjust the position on the track mechanism.

I've tried the Initialization/Teach Process that is used on the H3s (see below) but that was ineffective. I've also tried the process that I found for Tahoes/Suburbans in my year range ("Press and hold the Close button for 30 seconds until you hear a clicking sound from the motor.")...that didn't work either.

If anyone has any other guidance, that would be great.



HUMMER H3 - Initialization/Teach Process
"Ensure that all electrical harness connectors are connected.
Turn the ignition to ON.
Completely close the sunroof window with the manual close switch.
Press the sunroof vent switch to the vent open position until the sunroof window stops in vent location. After the sunroof reaches the vent position, release the vent switch and press and hold the vent switch again for approximate 10 seconds. Notice the rear edge of the sunroof mechanism will move, after the movement ends the Initialization/Teach Process is complete.

Important: The initialization/teach procedure is not complete if the battery and/or ignition power has been interrupted during the process.
The Initialization/Teach Process must be restarted if the procedure is not carried out completely. Verify the operation of the sunroof in all positions "

[Rico001]

I have not seen this as a problem with our H2 but I wonder if at highway speeds and driving with the windows down is not a big part of the problem to begin with?
Maybe since it is so hot / humid here we always roll up the windows and run the a/c on high that we never would notice anything wrong with the sunroof till it leaked.

Good luck to you

[guruerror]

Resetting the timing and synchronization of the motor did the trick.

Thanks to HUMTECH and my local ex-Hummer dealer (Criswell Performance) I was able to get the official GM instructions on the process. At first it seemed a little daunting, but literally took 30 minutes and involved 8 bolts/screws (4 of which I think I could have left in.) My biggest concern was that it would be difficult to get to the motor, but it's completely visible and accessible once you remove the ceiling console (see image).

I'm including the documentation below...I honestly believe you can skip step 1 (saving you those 4 bolts I just mentioned). I saw no reason or need to remove the glass to re-sync the motor.

Before starting, make sure you adjust your sunroof to a position where the glass is firmly seated and you get no (or the smallest amount of) give when you try to move the glass up and down. Mine was seating a little high when it thought it was closed, like it was starting into the Vent position, so I kept tapping the Open position on the switch until the rear of the glass hunkered down a bit more. At this point the glass became much firmer, then I started in with the process below.

Once complete I made some adjustments to the height of the glass using the four torx where it connects to the track, opened and closed the sunroof a few times, and took it for a test drive. At 75mph...no bouncing, vibration, movement, or noise.

FIXED.

[glennf1]

To add to this, on mine I have to keep the sunroof wind deflector on. If I take it off the wind pressure moves the sunroof enough to let wind noise through.

[glennf1]

I finally had to do this today as my sunroof has gotten more loose over time.

As mentioned, you do not have to take out the glass. In fact, it's easier if you leave it in because you can push up on it as you click it open until the track doesn't have slack. Don't worry about the glass position, you're watching the track on the sides. Then it's just two phillips screws for the overhead console and two bolts for the motor assembly. Follow the instructions to reset the motor. On step 8, it's not one quick click. Press and hold about a second then release. If the motor stops when you release, you didn't click it long enough and it won't reset. The motor will run for a few seconds after you release the button. I then adjusted the rear of the glass until flush with the roof by loosening the two torx screws.

Thanks to guruerror for the info and forums like this... I'm old enough to remember having to get the old chilton manuals and try to figure stuff out. Now it's just a quick search away