Now in a site permanently and checked this morning at 65F. No operation. The slides were extended previous afternoon and worked fine in 84F temps.
Jammed a pair of small needle nosed pliers under the rocker switch on the dash to activate 'Extend' while I went down and climbed in under the slideout and probed around the hydraulic assembly with my meter. Couldn't find a solid 13V anywhere I probed! But did see my meter readings swinging low to high low to high. Reminded me of a poor ground connection.
Anyway, while delicately probing around the smaller wiring, I touched one 16 GA wire and WHIRRRRRR the motor takes off. Scared the living you know what out of me. Jerked back in that small space in a slapstick effort to avoid being eaten by the motor. You'll just have to imagine it, but it was comical.
Was not expecting the motor to start because of where and how I was probing at the time.
Anyway, with the lack of solid voltage anywhere, I'm now thinking that I've got a corroded ground lead to the slide solenoid. I'm going to remove them all and clean them all up later today. It gets up to 80F here, and the assembly is in the shade so comfortable to work on. Glad I waited.
Stay tuned...