Odd power problem - JeepForum.com
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post #1 of 4 Old 07-22-2021, 10:41 AM Thread Starter
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Odd power problem

Ok, I have an electrical issue. Itís a 1989 with the 4.2 and a manual trans. I went out the other day and no power to anything. I replaced the relay on the firewall. I immediately have light but when I turn the key to start it I get a click and then no power to anything again. I unhook the battery then hook it back up and I have lights again. Turn the key to start and it all goes dead again. This is driving me nuts. Any ideas? Thanks and any help is appreciated!

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post #2 of 4 Old 07-22-2021, 10:45 AM
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I'd start with checking voltages into and out of the ignition switch (the actual switch behind the dash on top of the column) and checking the condition of the battery cables (they're known to corrode inside the cable).

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post #3 of 4 Old 07-22-2021, 11:02 AM
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A corroded connection can do this. When cold it has reasonable continuity, however once you put load through it, it heats up locally and the resistance goes way up.

with key on, check voltage drop between battery + and various points along the way.

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post #4 of 4 Old 07-26-2021, 01:24 PM
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Remove both battery cables at the battery. Naturally check the connectors to see if they are clean and in good condition and are on properly. Then grab each one by the connector and twist it back and forth rather vigorously at least a half dozen times. Now grab them and bend them out shape pinching the cable back onto itself. Put the cables back on. IF the battery is fully charged hit the key and see what it does. If it has a fully charged battery and it fires up I would also suspect that the cables are all green underneath the insulation......Replace them!

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