Transmission will not shift into drive from park

JT2020

MEMBER
2004 FORD F-150
5.4L
V8
4WD
AUTOMATIC
220,000 MILES

Truck listed above is an FX4.

With the heater switch on (heater not working), and headlights on (also not
working) my truck wont shift into drive from park. Also on my dash my hazard
lights are solid on with a high beam light on, this is when the going into gear
doesn't happen. What could this be from? Keep in mind that if the heater switch
is off or the headlight switch is off, the dash lights for my hazards or my high
beam light is off I can shift into drive from park. Any ideas?

3 Replies

STEVE W.

MECHANIC
13,475 POSTS

So you mean the heater and headlights also don't work? Then if you switch either one on the shift interlock also doesn't work? Does the engine start and run okay, any lights on the dash?
Which part of the heat doesn't work? The blower motor or the entire control unit? Do the parking and other lights work, just not the headlights?
Just trying to sort through what doesn't work in addition to the interlock. It sounds like a power problem but it could be a bad ground depending on which things work versus what isn't. Has there been any wiring changes recently like a replacement stereo or?

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Wednesday, March 24th, 2021 AT 1:15 PM

JT2020

MEMBER
2 POSTS

I actually just got it fixed. I check the ground under the fuse box and there was a rusty spot the where the wires were ground to my truck. When I grabbed them to see if it was lose, it pulled all the way out. I then drilled a new hole up above it, scratched off the paint around it, and placed the ground wire there and now it runs perfect.

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Wednesday, March 24th, 2021 AT 1:15 PM

STEVE W.

MECHANIC
13,475 POSTS

Great to hear. Grounds and powers are causes of a lot of issues. You may want to look at the others as well as some prevention.
Thank you for using 2CarPros and thank you for posting your repair. That may help another person with similar issues.

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Wednesday, March 24th, 2021 AT 1:15 PM