1999 Seville STS rear passenger regulator replacement – howto

1999 Seville STS rear passenger regulator replacement – howto

Bad noise from rear passenger window when my son try to operate it, it had been working perfectly up to then. Window stuck half way, lots of duck tape to seal as we were on a 1400 mile road trip…took the duck tape with me…good job.

Now the fix, and tools.

Time taken ~ 2 hours.

1 x trim removal tool kit from Harbor Freight, around $5 and worth every cent makes things so much easier
1 x big crosshead screw driver – to remove exterior trim
1 X small cross head driver – to remove exterior
10mm socket – to remove regulator from door frame/metal
A box to stand things on
Epoxy resin

First, locate all the screws/bolts, there are 2 hidden ones by the door pull/handle, in the well underneath the leather trim, pries up the bottom of the leather, it is Velcro’d on or something, any way, it lifts up like a little flap, underneath there you will find 2 large cross-head screws which you undo.

Now look along the bottom edge of the door trim, you should find one black screw, undo this, next, remove the plastic trim/panel in the well for the door opener/handle, the lever you open the door with, there is a screw under there.

Now prise up the ashtray and window switch unit in the door arm/rest, this just clips in, pries it gently along the shortest edge, it comes out pretty easily, then undo the electrical connector.

Next, using your trim removal tools, pop out the fasteners along the outer edges, the entire door trim panel can now be lifted out with a bit of gentle persuasion, I then stood the panel on a box so as I could unclip the door mechanical cable from the door opener/lever, the box came in very handy through out.

You now have to remove the white plastic fasteners that keep the inner black plastic panel onto the door, they have a little pin in the middle which you push halfway, then gently pries them of, also unplug all electrical connectors and remove the panel.

I then unscrewed all the bolts ( 5 in all ) that keep the regulator/motor unit attached to the door, seeing as the window was stuck halfway down it wasn’t wanting to come out, so I loosened the window guide to the left of the glass, and completely undid the lower one. I then loosened the bolts that clamp the glass to the regulator, and then placed blankets in the door to support everything, just in case anything dropped out, if the window should drop it will just rest on the blankets. I then pushed the window all the way up and jammed it up there. The regulator/motor unit then easily came out, what really helped was loosening the guide on the left.

I then examined the old unit, the top pulley was broken in pieces and the cable wrapped and jammed up in the drum, it was beyond repair, I ordered a used part to replace it.

I noticed that all of the plastic/nylon parts on the old one had fractures, still functional, mostly, but not good, I then compared it to the replacement, and this also had the fractures in the same places, so, on the replacement unit, I decided to smother them all in epoxy resin, being careful not to get any where important, this may increase it longevity, seem to be worth a try as it was so simple, I also applied grease to the relevant places.

Putting it all back together was pretty much the reversal of the above, but a handy tip, when putting the regulator/motor unit back, screw 2 of the bolts into the regulator first (there are 5 in all, use the 2 that are different to the other 3, they have red thread lock on them, put one at the top and one at the bottom), you can use these 2 bolts to locate and hang the unit before finally doing everything up, it is a great help doing this.

Useful trim removal tools

Useful tim removal tools


Plastic fastener, push pin halfway to release

Door trim flap (circled in red)

Door trim flap (circled in red)

Door internals


Regulator fractured plastic before epoxy

Epoxy smothered over fractured parts, an attempt to improve the life on the unit

Epoxy smothered over fractured parts, an attempt to improve the life on the unit


Broken pulley on regulator – the cause of all the trouble, or possibly a victim…maybe the cable broke and caused the pulley to fail…who knows…


About hedscratchers

A UK ex-pat now living in the USA.
This entry was posted in Cadillac Seville STS (Pre-2003). Bookmark the permalink.

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