# 1997 mercury grand marquis

**URL:** <https://community.cartalk.com/t/1997-mercury-grand-marquis/67449>\
**Category:** Maintenance/Repairs\
**Tags:** ignition\
**Created:** [August 27, 2011, 8:54pm UTC](https://community.cartalk.com/t/1997-mercury-grand-marquis/67449 "2011-08-27T20:54:40Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![eric16](https://avatars.discourse-cdn.com/v4/letter/e/aeb1de/32.png) [@eric16](https://community.cartalk.com/u/eric16)\
**Post date:** [August 27, 2011, 8:54pm UTC](https://community.cartalk.com/t/1997-mercury-grand-marquis/67449/1 "2011-08-27T20:54:40Z")

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I am wanting to install a tach in my new car. I know what the wires on the tach do and how I need ti wire it up in the car. the only problem I have is I am not sure which wire on the coil is the negative. My old 77 ford truck was easy to do. but does any body know on this car ? please.