1969 Cadillac Station Wagon - Door Locks and Tailgate Power window stopped working

All of a sudden my power door locks are dead. I tried both switches, drivers and passengers. Totally dead. Also I noticed too that the rear tailgate power window has completely stopped working. Went from working fine to dead. No in between. (the side door windows all work fine)

I have a feeling the problem is related but not sure. My first instinct was to check the fuses but I didn't see a fuse labeled "door locks"

PS: The tailgate window switch is located on the lower part of the dash near the drivers left knee. The tailgate window is also supposed to operate by a keyhole, but I am missing the key to that so I'm unable to test it.... and I cannot open the tailgate with the window up because of the way the window rolls up into a channel AND you have to lower the window to get access to the latch which is on the inside. I would have to crawl over the 2nd and 3rd row seats to take the carpeted panel off to access the power window motor, etc.

I'm thinking its some sort of fuse or relay which has caused both of these items to fail at the same time but I looked at all my fuses appear to be good.

Any help?

 

Was it a coachbuilt custom or was that a regular Cadillac model? You might have to look at the wiring for the vehicle they based the wagon section on (Olds, Buick, Chev, Pontiac?).

There's some period Cadillac Wiring diagrams here. (Bottom right hand side)
http://www.oldirononline.com/

 

I recall GM power windows being protected by breakers rather than fuses.
Whatever circuit operates the locks would probably have been a fused one but if a coachbuilder used this circuit to operate the rear glass it stands to reason they may have substituted a breaker into that slot.
If you see another breaker in the fuse box check it's continuity or try substituting a 20a fuse for it and see if that works.

 

When I worked at the Pontiac/Buick Garage in 1975/76 we had three cars come in with power window problems in one week and all were traced to a bad relay behind the drivers side kick panel.

 

Does the tailgate window work with the key off? Power door locks usually work with the power off, some cars the tailgate window too. On my '71 Vista the locks feed directly from a breaker on the firewall behind the brake booster and I'm pretty sure that also feeds the power window relay. The breaker is just a small rectangular thing with 2 threaded lugs, screws to the firewall, rubber cover on it. Others do have a circuit breaker that plugs into the top of the fuse panel that basically does the same thing.