: Fixed my Automatic Level Control but....



turbojimmy
08-08-11, 03:08 PM
I'm a little worried about the cause of the problem.

If you recall, one of the mini-wedge switch wires had corroded on my car. It was all blue/green and rotted at the connector. I spliced it back together and the switch operates the lights as it should, but I have one light with no power to it. I suspect I'm going to find the same corrosion at another wire that ultimately feeds that light.

Back to the topic at hand....my automatic level control wasn't running the compressor. If I manually grounded the correct wire at the relay, the relay would function and run the pump. However, it didn't work automatically. It was strange because the "up" command and "down" command gets it's signal from the same ground wire back at the sensor. I get "down" commands (the pump vents) but not "up". I verified an open circuit between the sensor (back at the rear axle) and the pump (up by the left front wheel). That's A LOT of wire to trace.

Undaunted, I started by tracing the yellow wire in question from the pump to the harness. There's a connector mounted to a bracket by the engine management computer. As soon as I touched the yellow wire at that connector, it broke off. It, too, had corroded at the connector. I cut back the corroded part and spliced in a new section of wire. Now the ALC works as it should. That makes me happy, but the thought of countless other issues like this lurking doesn't.

I don't know what is causing these wires to corrode. The car is clean underneath - not a rust bucket. I know it sat for a very long time, however. According to CarFax it could have been as long as 10 years. It must have sat in a garage or something because it doesn't have the undercarriage rust of a car that sat in someone's yard or driveway. But the wire corrosion is perplexing.

Hopefully there won't be too many more of these....

alexgrig
12-15-16, 05:07 PM
a week ago the same problem-yellow wire was broke down inside insulation, right after P102, where wires harn incomin' to underhood from dash
http://forum.detroit.in.ua/download/file.php?id=40048&mode=view

cadillac_al2
12-15-16, 06:12 PM
I'm a little worried about the cause of the problem.

If you recall, one of the mini-wedge switch wires had corroded on my car. It was all blue/green and rotted at the connector. I spliced it back together and the switch operates the lights as it should, but I have one light with no power to it. I suspect I'm going to find the same corrosion at another wire that ultimately feeds that light.

Back to the topic at hand....my automatic level control wasn't running the compressor. If I manually grounded the correct wire at the relay, the relay would function and run the pump. However, it didn't work automatically. It was strange because the "up" command and "down" command gets it's signal from the same ground wire back at the sensor. I get "down" commands (the pump vents) but not "up". I verified an open circuit between the sensor (back at the rear axle) and the pump (up by the left front wheel). That's A LOT of wire to trace.

Undaunted, I started by tracing the yellow wire in question from the pump to the harness. There's a connector mounted to a bracket by the engine management computer. As soon as I touched the yellow wire at that connector, it broke off. It, too, had corroded at the connector. I cut back the corroded part and spliced in a new section of wire. Now the ALC works as it should. That makes me happy, but the thought of countless other issues like this lurking doesn't.

I don't know what is causing these wires to corrode. The car is clean underneath - not a rust bucket. I know it sat for a very long time, however. According to CarFax it could have been as long as 10 years. It must have sat in a garage or something because it doesn't have the undercarriage rust of a car that sat in someone's yard or driveway. But the wire corrosion is perplexing.

Hopefully there won't be too many more of these....

This has been my experience over the years with the miles of wiring in Cadillacs; a lot of corroded power seat and window wires, These are the things I also worry about in airplanes when I see the huge bundles of wires running through them. It's always nice to find the bad wire causing the problem though.