Power Remote Exterior Mirror Repair  

Description
The outside power mirror is operated by a joystick type control located on the console.  The mirror glass is mounted to a swivel assembly that's fixed mounted to the mirror frame, which is mounted to the door frame.  The swivel assembly is operated by a pair of small DC motors in a rack and pinion arrangement.  By applying +12v or -12v to either of the motors causes the swivel assembly to move up/down or left/right.

My Problem
The power exterior mirror on my 1989 560 SEC stopped working in the up/down direction, left/right worked fine. While I had the center console apart, I decided to check the problem out starting with the mirror control switch.  After eliminating any obvious problems in the console area (loose wires, bad grounds, etc) I moved to the mirror itself (refer to job 88-905).  The plastic triangle cover plate has a plastic clip located at the top of the panel (see Fig-1).  Carefully pry the panel (close to the clip) away from the door frame.  I used a very handy tool designed for removing body panel clips I got from The Eastwood Company (see Fig-1).  I had to use a little more force than I felt comfortable with to get the clip loose and when it did come loose, it made a loud snap sound.  I thought, great, the clip broke, but it didn't.  The panel's plastic clip fits into a spring clamp that's attached to the door frame.  When the panel popped loose, that little spring clamp went flying across the garage.  So beware.
The bottom of the panel has two plastic tabs that simply fit into holes in the door frame and with the top clip loose, the panel just lifts out. 

	Fig-1
	Fig-2

Now carefully peel the padding material from the door. (Fig-4).

Fig-4

Unscrew the power connector and disconnect.  This connector supplies the power to the mirror's heater through pins 1 & 4.  Pin 2 is the common connection to the up/down and left/right motors.  Pin 3 goes to the up/down motor and Pin 5 goes to the left/right motor.  The connectors were very corroded, so I cleaned them, but that didn't fix it.  I checked the power to the connector which worked fine.  You should get 12v between pins 1-3 when activating the switch in the up/down direction (the polarity will reverse from one direction to the other).  You should get 12v between pins 1-5 when activating the switch in the left/right direction.

Remove the mirror from the door by removing the 3 screws.  Carefully pull the mirror loose from the door frame, the rubber gasket tends to stick to the door, so be careful not to tear it.  

With the mirror on the bench I applied 12v to the appropriate contacts and only got movement in the left/right direction.  That pretty much only left the motor or some wiring inside the mirror assembly.  Figuring out how to disassemble the mirror was fun.  

If you look inside the mirror assembly you'll see a large retaining spring clip that fits into slots around the mirror mount and swivel assembly.  Fig-5 shows the mirror dismounted from the swivel assembly. Using a button hook or similar, hook the ends of the retaining clip and unlatch both ends.  Use the hook to loosen the clip and the mirror can easily be removed.  Examine the motor assembly and gears looking for any obvious damage (stripped gears, broken parts, etc).  If anything is broken, those parts will have to be replaced and I'm not sure whether they can be purchased separately.

Fig-5

Remove the two screws to either side of the swivel assembly to remove the rear cover.  Remove the 3 screws inside the swivel assembly to remove the assembly from the mirror frame.  Remove the rear cover of the swivel assembly to expose the solder connections to the motors (Fig-6).  Remove the wire retainer and make a diagram noting the original wire configuration.  Unsolder connections and the jumper bar with the appropriate solder gun, being careful not to use too much heat as to melt and damage the plastic parts. 

Fig-6

With the swivel assembly loose apply 12v to each motor.  I used an ammeter to verify the motor drew current to tell me whether I may have an open winding or bad brush.  Considering the minimal use these motors get, I doubted the brushes would be bad.

The rest of the disassembly process is rather involved and takes a good deal of patience and a delicate touch as you don't want to break any of these plastic parts.  In order to remove the motors, you must carefully pry one end of the axle from the motor mount (Fig-7).   Then from the underside, use 2 small flat blade screwdrivers to carefully pry the white axle assembly from the center of the motor carriage.  From the top side, using a flat screwdriver,  carefully pop the ball joints loose at the end of the rack gear.  This will release the swivel mirror mount from the motor mounting assemble.  Be careful not to tear the rubber boot.  Carefully note component orientation for reassembly.
Then again from the underside, carefully push the 3 assembly rivets out. Very carefully pry the top half of the motor mount from the bottom half.  Note that the motors clip to the bottom of the motor mount and these clips may have to be gently pried off the bottom mount as you are prying the top portion off.  The motors are also clipped to the top motor mount.
 

Fig-7

Figure 8 shows the top half (with motor) removed from the bottom half.  Note the motors have to be simply unclipped from the top half of the motor mount. Be care to observe the orientation of the motor, spring, pinion transmission and rack, as this will come apart when you release the motor.

Fig-8

With the motor free, try to manually turn the shaft, if it doesn't turn very easily check the other end.  Mine was rusty and seized at the brush end (plastic end) of the motor.  Try to clean most of the rust off the end of the motor shaft with emery paper and WD40 to allow the end cap to slip off without damaging the end cap.  Carefully bend the crimped tabs back on either side of the motor, which will release the plastic end cap off the motor.  Very slowly pry the plastic end off being careful to not damage the brushes. See Fig-9 (sorry about the focus).  Clean the rusty end up as possible with the emery paper and WD40 and reassemble.  Then test with 12v battery.  Repeat process on the other motor if required.

Fig-9

Reassemble the motor carriage, carefully installing the motor, spring, motor clip, transmission and rack as shown in Fig-10 making sure the flat shaft end properly meshes with the transmission.  Note the spring is not seen here, but is installed with the small opening at the motor end. Also note the solder tabs orientation.

Fig-10

Then carefully install the top half of the motor carriage into the bottom half.  Make sure the rack gear ends go into the corresponding holes and the bottom motor clip are in their corresponding holes.  Slowly press the two halves together careful not to force anything.  Then press the assembly rivets in to the top side.  Replace the rubber boot and mirror swivel mount.  Carefully reinstall the axle assy. by inserting one end into the swivel mount and pressing the center clips over the motor carriage mount and then pressing the other end of the axle into the mirror swivel mount. Press the 2 rack ball joints back into the mirror swivel mount.

Resolder the jumper bar and wires to the appropriate motor solder lugs.  Route the wire through the molded channels in the underside of the motor carriage assy. Replace the wire retainer and rear end cap.  Screw swivel assy. back on to the mirror frame.  At this time test mirror swivel as before by applying 12v to the appropriate connector pins.  Test for full range of motion in all directions.

As seen in Fig-5 install the large spring clip on the backside of the mirror.  Reconnect the heat power connector to the back of the mirror.  Then simply press the mirror over the mating swivel mount making sure you hear the spring click and the mirror is securely attached.  Replaced exterior rubber boot, making sure all the mounting holes match up and that rubber seal sets flush with their mating surfaces.

Mount the mirror to the door frame in reverse order as the disassembly.  Before connecting the power connector clean the contacts if required.

Disclaimer
This procedure should be used as a reference and some applications may vary.  The author is not responsible for variances and this article may not be 100% accurate.  So proceed with caution and the reader accepts 100% responsibility for the results.

by Chet Hwilka