Location of jack on 09 f150 regular cab - 2009 Ford F-150

SOURCE: Install Rear Speakers Ford F150 1997 Regular Cab

you should not have to remove the panel by taking the four phillips screws out of the speaker grill you will pull out through front

SOURCE: check engline light on a 2003 f150 why?

with the truck running feel around the engine vacuum lines under the hood on the passenger side. listen to see if you can hear a vacuum leak or if you can feel one with your fingers. it will probably be close to the firewall close to the rear of the valve cover

SOURCE: 2003 Ford F150 Regular Cab passenger side floor board wet at time

prob. the heater core located under the dash the lines go thru the firewall to the engine. on a '98 you gotta take alot of stuff off to get to it air bag, dash etc. alot of time but the parts arent too much $$