Had unhooked horns and tried the horn buttons, heard the realy click perhaps 40 times, off and on. In the process of checking DTC's and working with doors open, apparently ran battery down. Jumped it, was fine, until I checked a-b connectors again, and the engine coolant fan running ran it down. Turns out, it had a dead cell. A 4 year battery, lasted almost exactly 4 years. Incredible.
On the road again, horns didn't work. So replaced the $6 relay, after doing $100 of labor to get to it. Back to normal, meaning "work every time, sometimes, or never." MY 91 horns have a two pin connector, one is ground, but removed the chassis grounds (2) at the headlights, cleaned terminals, but they were probably fine. The ground path is thru the wire crimp, to eye terminal, then thru nibs under terminal, which have to bite thru two coats of paint, to bare metal. The screw and threads are incidental, or casual ground, as UL would say. Anyway, I have grounds at the horns -which ARE GROUNDED MAYBE SEVERAL PLACES, BUT NOT DEPENDENT ON THE LARGE CHASSIS GROUND.
Have decided that the horn button(s) are not making ground consistently, but it still does not make scientific sense. Also, for some reason, my chime alarms started working again. I was not in that area when replacing horn relay. Another mystery.
If anyone knows why the fan comes on when a-b of ALCL are jumpered, with key on run, let me know. If normal, I can quit worrying. Incidentally, did have one VATS code 46, but cleared it and it is now empty of DTC's.
While I had the energy, changed the auto trans fluid and filter, first one since 1974 or so. Noticed that the filter pickup tube o ring -aftermarket orange type- remained in the trans cavity, but I was watching and pryed it out with screwdriver. Likely anyone not paying attention would have installed the new filter. Which may have worked, except it would have two seals, and be too low by the thickness of the seal, about .200".
saludos.
