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Discussion Starter · #1 ·
When driving during the day, the tach works normally, and is almost accurate...go figure! when I turn my park lamps or headlights on, the tach and boost guage stop working After a short time, the 5 amp guage fuse pops. I have replaced the fuse a couple of times but it still does the same thing...any thoughts???
 

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Not really... :)

The gages fuse is supposed to be a 20 amp fuse, as per the book.

The inst lps fuse is supposed to be a 5 amp fuse.
When you turn on the parking or headlites, the instrument panel lites should come on via the 5 amp fuse.

The tach should be independent and depend upon the 20 amp gage fuse. It looks like, at first glance, that it should have nothing to do with the lights with regard to function, not function.

Therefore, I am in my usual confused state.
 

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Discussion Starter · #3 ·
Sorry Steve, I got them mixed up. It is the 5 amp INST LPS fuse that is blowing. The fuse lasts for about an hour after I replace it, the funny thing is when the fuse is blown and I turn the lights on, the tach/boost lights go out, and when the lights are turned off, the tach/boost light come back on. If the book says that the 2 fuses are not related, then I am confused as well. Where would I start looking for broken/bare wires?

Electrical gremlins :mad: ....gotta love 'em wink

Jay
 

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Jay, it is more complex because the fuse does not blow instantly...it begs the question, Is it a too heavy current draw that eventually causes too much load and a blown fuse, or is it a matter of the right movement grounding out a wire?

The inst lps fuse gets its power via the light switch thru the dimmer.

A gray wire from the fuse splits into 8 or 9 gray feeds to various lights. I think I would look at the console shift light. That gray wire is known to get pinched or cause a short.

Other feeds off the splice go to the instrument panel, tach, trim plate, heater control head, radio, convenience center, and defogger.

If you don't have a console, the light is in the ashtray.
 

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Discussion Starter · #5 ·
...a new twist. Steve, I have replaced the 5 amp INST LPS fuse again and now when the lights are off, the fasten seatbelt light comes on, when I turn on the park/headlamps, the fasten seatbelt light goes off. I checked the shift indicator light wiring and it all looked good and metered ok. The seatbelt light has flickered on and off since I have bought the car. Could the module under the dash be the culprit??

TIA
Jay
 

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Jay, it is just cursed.

That fuse also feeds the convenience center which is the module tucked under the dash. When it goes bad, it will flicker the seat belt light, or make it stay on when it should be off.

Maybe start with unplugging the center and seeing what happens?
 
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