My Hints for the Infamous Sunroof Repair

I spent hours reading the forums and watching videos regarding repair of a stuck sunroof. Now that I am done, I will share some of my lessons-learned and hints with the community. Reference other forums for the full process to remove and repair the sunroof assembly. I am splitting this into Mechanical Hints and Electrical Hints.

First, read the FSM for Sunroofs. And the 1986 Mazda Training Manual which covers Sunroofs – very helpful – better than the FSM.

(Also, for those folks that coax their Sunroof fully open by physically pushing on it at, or near, the Tilt-Up position, read my theory down at the end of this posting session.)

 

Mechanical Hints:

DISASSEMBLY – Take reference pictures. And if you can, rebuild one side of the sunroof assembly at a time. This is an intricate piece of engineering. Centimeters and millimeters matter here.

BLACK METAL FRAME – It’s probably rusty under the Aluminum Guide Rails. Its light pressed steel so be careful welding in replacement steel or you will blow through the metal.

WIND DEFLECTOR – Its 4 screws, get it out as soon as possible. Before the little black tabs break off.

ALUMINUM GUIDE RAILS – Clean up nice with light cleaner and scotchbrite pad.

CHROME SCREWS – Usually rusted in place. Remove with a screw impactor. New OEM ones are pennies from Mazda (Part No. 9977-40-408).

SLIDER CABLE ASSEMBLY - The slider cable assembly c/w the end trolley must be fully functional; it is the heart of the whole sunroof system. If the cable portion is rusty, you have three options:

a)source a new one – tough and expensive.

b)buy a Mercedes cables and connect them to the aluminum end trolley.

c)If the cables are not broken, soak in Evapo-Rust for two days. You might get lucky – I did.

And these cables just pull out of the brass tubes. And no, the riveted plate below the electric motor does not need to be removed. Just remove the geared electric motor.

SLIDER TROLLEYS – The source of all sunroof evil (Picture #1). They are factory connected to the slider cable. The trolley body is aluminum and usually fine; however, the little nylon wheels don’t have bearings, they are just peened over with metal from the trolley casting itself. They jam up, grind, and then explode. I found some nylon wheels from Hillman (see Picture #2) and filed and drilled them down to size. If you have a small lathe that might help.

BRASS TUBING – Clean with break cleaner and wire brush. Leave in place if possible, because there is a lot of tension on them in the metal frame – and they are surprisingly hard to reinstall-again, millimeters matter. When you refeed the slider cable back in, use lots of lithium grease.

 

Electrical Hints:

BENCHTEST – Hook-up a 12v battery to test outside of the car. You will be less frustrated in the end. Use an inline fuse (15 AMP worked for me). Negative is to the ground (see Picture #4). Positive to the one green wire lead (yes, green of all colours).

RELAY 1 – Pretty easy to benchtest check with a Multimeter. You can trigger it with a 9V battery.

RELAY 2 – Potentially the source of a lot of problems. This is the brains that stalls the Sunroof at the Tilt-Up position, by breaking the power circuit when the electric motor’s Limit Switch sensor is triggered.

Then Relay 2 does an automatic reset. Push the sunroof button again, and the sunroof opens all the way now. It all done with a simple relay, two diodes, and a single transistor.

Good news! Its easy to split open this relay with a slotted screwdriver, troubleshoot, and replace the components (Picture #3).

a)Check the two diodes (I replaced one with 1N4077) with a Multimeter.

b)And check the single Transistor (original part 2SC1741) with a Multimeter. Google and study the pinout layout of this NPN Transistor, because the layout is abnormal (the Base leg is not in the middle). I replaced mine with a 2N4401 Transistor (which has standard layout, with the Base leg in the middle).

ELECTRIC MOTOR (with Limit Switch sensor) – Has a Limit Switch trip switch, which works with Relay 2.

Before you reinstall the electric motor, using an allen key to drive the motor, align the gearing at the point it is meant to trip Relay 2. Study the poor quality rendering in the FSM showing how to do this (and look at Picture #5). Move the whole Sunroof panel to the point you want it at the Tilt Up position. Now reinstall the motor.

(*FULL DISCLOURE – I could never get the Tilt-Up position to work – so I may have this wrong. I would love it if someone can confirm if I have this correct).

 

My theory on why a Sunroof needs to be coaxed to full open:

Normally, the Limit Switch sensor on the electric motor, working with Relay 2, cuts 12v power to the electric motor when the desired Tilt-Up position is reached. However, in a scenario when the sunroof is moving with some momentum, and you apply some pressure to keep it moving, you are basically pushing past the cut-out zone of the Limit Switch sensor. Then power kicks back in and your sunroof goes all the way open.

The solution: The Limit Switch sensor on the motor possibly needs to be replaced. But I would turn my attention to the two diodes on Relay 2 – they look like the weak link to me – and they are cheap and easy to replace if you can get to Relay 2 (above the headliner, near the rearview mirror).

But it’s only a theory! If you have any success, let us know.
Keep on truckin' !

 

This is a great writeup! Thank you for making it and sharing with the community!

 

This is very helpful, and I'll be using it sometime next year when I get to my sunroof. Mine works pretty well other than needing some help on the initial upwards movement (due to a worn plastic part). When I get to that step I'll take a picture of the plastic part and add it here in case anyone else has the same issue.

 

Also, if need be, I can stick the thread if everyone feels its helpful enough to do so. I think its a great writeup.

 

I vote for a sticky. This is a pretty comprehensive writeup that I plan to come back to, and has non-broken link pictures too. Thanks to the OP for putting this together.

 

I concur with making this a sticky, very useful info here, thanks to the OP for posting!

Having done a complete sunroof resto on my S5T2 a few years ago, I can add another tip to help out those of us that still have the S5 motor-mouse seatbelts. Mazda left out a step in the '89-91 FSMs that hinders removal & reinstallation of the entire sunroof assembly. It was easy enough to figure out a work around myself, which is documented in this thread here: https://www.rx7club.com/2nd-generati...belts-1155003/

 

Thank you for the writeup. I will be trying this as well. I did a cleaning a few years ago and it helped a bunch. The motor still has a hard time in between closed and tilted, so I might try cleaning and testing diodes and relays.

 

Thank you for the writeup. I will be trying this as well. I did a cleaning a few years ago and it helped a bunch. The motor still has a hard time in between closed and tilted, so I might try cleaning and testing diodes and relays as you suggested. Great pointers!

 

the issue to me sounds like a weak clutch mechanism built into the motor. you can hear the motor turning but get the reward of the sunroof just sitting there laughing. the clutch is to prevent premature motor failure if the sunroof is stuck. i have never felt the need to pursue it though, a little nudge always gets it working. a little extra tension on the clutch couldn't hurt, they have always been problematic in this way. however i don't know if this is a spring operated clutch or just a friction one, the latter would be much more difficult to overcome without designing and 3d printing your own parts and experimenting while installing and removing the sunroof many times to get the desired result(unless the motor can be taken out without complete removal and reinstalled as well. the clutch should be built into the main drive gear in the motor assembly.

note these are just assumption from working on cars my whole life, i could be completely wrong as to how this clutch operates. i have never had issues with the vent versus full open operation. i just press the up button until the sunroof stops at the vent position, release press and hold the button again until it is full open. i never felt the need to remove the sunroof to service it, i clean the guide rails and lubricate them every few years with the sunroof in the full open position.

waxing my sunroof inner roof lip and cleaning the sunroof felt seal usually gets it working without assistance for a while.

 

Since I got my FC in 1999, it spent it's life garaged with minimal time out in rain/bad weather, so rust & corrosion was a minimal issue on mine. Nonetheless, the sunroof mechanism failed - like most, I was able to get it to move up & open by nudging it up. This got progressively worse till it got to the point where it was hard to open even with the Allen wrench tool. At that point, I removed the sunroof panel to try to thoroughly clean & re-lube everything I could get to without taking apart the whole sunroof assembly. After the clean & lube exercise, and with the panel still off, I noticed that the lift arms had no problem popping up and moving fore & aft as they should by working the motor, BUT I noticed that one of the arms (forget which side) would pop up a little quicker and start moving quicker than the other - so the arms, and the cables/trolley that moves them were out of synch. Reinstalling the sunroof panel mechanically binds the two arms together, which has the effect of locking up the whole mechanism.

The sunroof mechanism works similar to a rack & pinion steering system, except in this case the "rack" is in 2 parts (one for each side) and is flexible. Once they deform or stretch (from being forced open too many times), the two sides get out of synch and it locks up the mechanism.

 

Great write-up and read

Looking to put my headliner piece back onto my sunroof during which time I might be interested in fixing some of the existing issues with it.

 

Thread has been stuck at the top. This will definitely more than helpful to many people in the years to come. I'm sure I will need help with the sunroof in my 10AE. It doesn't always want to work properly and needs a little assistance opening.

 

i really don't think this is a fix, the repairs inadvertently caused less friction to the sunroof in the roof frame. the issue is the clutch is simply too weak from the factory. we've all had a car where you left it out to sit for months and months, went to open the door and the door seal wants to hold the door closed, the same principle works with the sunroof and the factory clutch setting is far too weak to account for it. it can barely open a freely working sunroof.

 

Based on notanymore’s theory regarding a Friction Clutch, or a Spring Operated Clutch, I split the sunroof gearbox open to see if the torque or force in the assembly could be increased. Perhaps someone will experiment with changing the gearing. In the meantime, my hints on how to increase the compression in the system, and refresh the Friction Clutch Disc are below.

 

Hints for the Friction Clutch in the Sunroof Gearbox

Torque Adjustment of the Friction Clutch:

Bend down the keeper tab washer. Hold the main shaft stationary with an allen key. Turn the nut clockwise with a wrench (Picture #1) to increase compression on the Friction Clutch Disc. (Yes, this is same shaft and allen key used for the manual sunroof override).

If you know the factory torque setting – let us know!

 

Splitting the Gear Box:

Is relatively easy and can be done in 30 minutes.

1) Remove the Cover Plate Group: 4 screws and a snap ring. (Picture #2)

2) Main Shaft & Sun Gears - Remove the exterior nut on the main shaft: keeper tab washer, allen key, and wrench (again Picture #1). Keep an eye on the six little shims (Picture #2) - they can disappear quick.

3) Secondary Shaft & Planetary Nylon Gear – Pull this shaft and single gear out (Picture #2). Otherwise you will struggle with removal and reinstall of the main shaft assembly. Its only 2 screws and some force applied.

Note the Concave Pressure Disc: During reassembly, as you bear down on the aforementioned nut, you are putting this disc – and the rest of the Main Shaft components – under compression.

 

Refreshing the Friction Clutch Disc:

1) The Friction Clutch Disc is probably burnished from years of spinning. Dry sand with 600 grit sandpaper (Picture Collage #3). It’s the only true consumable in the whole assembly.

2) Clean and 600 sand the receiving Metal Mating Plate.

Hint - Keep the Friction Clutch Disc free of grease. Be conservative when repacking the gear box. Don’t use spray lubricant.

Preventative Thoughts – Over the years, as the phenolic face on the Friction Clutch Disc wears down, compression disappears from the assembly. Then the Friction Clutch Disc is prone to spinning, and developing a burnished face – leading to more clutch spinning and your stalled sunroof - it’s a vicious circle. Solution – keep the main shaft under factory compression.

 

thanks for going out of your way to investigate that, hopefully the added tension will allow the clutch to not spin ***** nilly like it tends to do instead of moving the mechanism first.

the clutch is meant to save the motor from burning up or wiring from overloading and popping the fuse, so try to find a happy medium where it still can slip if the sunroof does wind up completely jammed up. most people have enough common sense to not hold the power button for a minute while nothing happens though, but the manufacturers build in these failsafes just for those people.

a simple test could be as follows:
place your hand on the sunroof and hold it down(at the center rear of the sunroof, not at a corner) then operate the sunroof and see if the motor whirrs or sounds like it is completely stalled out. just don't apply power like this for very long. the motor should whirr like it is running and the sunroof fail to open, release hand and retry and sunroof operates normally.


also something to keep in mind, with the engine running those added ~2 volts do make a difference to the strength the sunroof motor puts out. i would try to do adjustments with the engine off rather than on.

but stuff like this is what this forum is for, to document how to do these sorts of things. i'm honestly surprised this has taken the whole life of this forum to ever be accomplished though, so know your work is appreciated.

additionally, is this compression nut accessible without removing the headliner? that would truly save people a lot of headache in doing this repair. i suspect not easily, because both allen key and some sort of crows foot would be needed in a rather small hole through the sunroof where the manual crank hole is. if the gear does not in fact need to be held with the allen then this should be doable without any real disassembly. ie pop out the headliner plug, tighten the compression nut 1/16th of a turn and retest. even if the gear must be held a workaround could involve a drill with a light clutch setting to impact the nut down slowly while testing.

those are just my thoughts anyways, i have never physically touched my sunroof innards as it still somewhat operates reliably. but there has been occasions when i had to give it the old helping hand. this would be a bit more of a long term solution.