1990 454 mag lost power
#31
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So, we need to find your purple wire.
What is hooked to the ‘I’ terminal on back of ignition switch ?
What is hooked to the ‘I’ terminal on back of ignition switch ?
#32
#33
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Ignition switches aren’t grounded, so someone used a black for something powered.
can you locate the terminal marked ‘I’ and tell us what color wire and where it goes to.
can you locate the terminal marked ‘I’ and tell us what color wire and where it goes to.
#34
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Here’s the back of an ignition switch i just got and installed for a friend few weeks ago whose plastic switch literally fell apart.
![](https://cimg8.ibsrv.net/gimg/www.offshoreonly.com-vbulletin/920x2000/076ce22a_4af5_4d6b_b4d5_d88921530979_3376649cfd6f78f03ead377dcf04270b239fb7c2.png)
![](https://cimg8.ibsrv.net/gimg/www.offshoreonly.com-vbulletin/920x2000/076ce22a_4af5_4d6b_b4d5_d88921530979_3376649cfd6f78f03ead377dcf04270b239fb7c2.png)
#35
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SB you're going to get a free upgraded membership for this one............
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Prestigeworldwideee (10-22-2022)
#36
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#37
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Ah, I just assumed the black wire was a ground and I didn’t test that either. I’ll see what I can see tomorrow, it’s pretty cramped in the dash underneath.
#38
#39
#40
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Just for quick test to make sure ignition switch is bad, hook purple to the battery terminal (b or batt) keeping the wire hooked to it, still hooked to it and start motor. If it runs, you have bad ignition switch, which it seems like due to your checking switch positions with multimeter.
Note: engine won’t shut off with purple wire hooked to battery power. You’ll have to unhook purple from it to kill the engine.
i have a 12-14 gauge wire with alligator clips to jump terminals for such things. Makes it fadter to diagnose, especially in cramped quarters.
Note: engine won’t shut off with purple wire hooked to battery power. You’ll have to unhook purple from it to kill the engine.
i have a 12-14 gauge wire with alligator clips to jump terminals for such things. Makes it fadter to diagnose, especially in cramped quarters.
Last edited by SB; 10-22-2022 at 04:23 PM.