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Old 05-30-2016, 03:23 PM
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Originally Posted by shoebox View Post
...Concours suggested I send my original harness to copy...
If the original harness was in fact 'original', of course they want it. When the car was new, it worked. That means all the wires and connections were correct, your limit switches had clean contacts and they were adjusted properly.

If your original harness wasn't corroded, fried or chewed up, there is no reason to change it. As you found out, instead of fixing problems, changing to something 'different' only makes matters worse. Yes, I know hindsight is 20/20 but I'm an electrical troubleshooter and in my experience, reinventing the wheel only sets you back and often causes different problems.

Yet again, I'm with John and his advice so I won't repeat it. He suggests using sound troubleshooting techniques to pinpoint the problem. If you find a bad component, change it but not before. Otherwise you will end up with a basket of good (and expensive) parts that cannot be returned.

One of our members recently had a problem with his Lincoln top. After all was done and working I asked him exactly what he found and what he did. He said the previous owner swapped two connections and he adjusted limits after 'working' each of them dozens of times. This is very typical. In reality, the wires were correct but the PO felt the need to make changes without testing the circuits. Bottom line: after straightening and troubleshooting the cost for parts was zero but it took him a few hours to troubleshoot.

If you are armed with a schematic and you can trace circuits, troubleshooting is not difficult because all the components plug in. That means you can unplug them to ring continuity with the power off. After proving the switches, turn power back on and read voltage at the relay coils and contacts.

Do not get distracted as you do each circuit one at a time. I liken troubleshooting to being on a road trip. You have a map. If you run into an obstacle (like your road is closed due to construction), would you go back home and start all over? In electrical, we find blocked paths by tracing them.

BTW, I never listen to these words: "Well, last time it was..." That will only cause you to buy more un-needed parts and it will usually not fix your problem. Use sound troubleshooting techniques and do not let anything distract you. - Dave
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