Ignition resistors develop a considerable amount of heat- - - - -That's why the wire is mounted in a ceramic housing. It needs to be mounted somewhere there's a constant flow of air across it- - - -under the hood and in the airflow of the fan if possible. Under the dash sounds like a possible source of odors, or maybe a fire hazard.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!