Brake Pedal/Starter Interlock Issue

2003 SR5. I got the truck used several years ago. Never even needed to press the brake pedal to start it. It stopped wanting to start. Replaced the battery, starter relay, and starter. It starts now, but only if the brake pedal is absolutely smashed to the floor. Otherwise, the starter does not get activated. Any suggestions on how to fix or bypass this? Thanks in advance.

 

Question, do you have to mash the brake pedal to the floor to activate the brake lights?

My first thought is that the brake lamp switch is out of adjustment, assuming the brake lamp switch is required to be depressed in order to activate the ignition. It is not on my 2000, but I do not have cruise control.

 

No, the brake lights activate with minimal pedal movement.

 

Any error codes if you hook up a scanner to it? The brake pedal switch has two separate circuits and I think only one is used for the brake lights. Could be the other circuit is bad or out of adjustment. The switch is pretty cheap and not too hard to replace, but I'd check for brake related codes first.

 

Thanks, I'll do that check and the brake switch is a cheap and easy fix, like you say.

 

I glanced quickly at the 03 FSM (Field Service Manual) and I do not see a correlation between the stop Lamp Switch and the vehicle starting. You can look through it yourself. A link can be found at the top of THIS THREAD

 

It looks like stop lamps and cruise control

 

Yeah, I'm not really sure of the connection to the starting issue, just remembered before I changed out my brake switch I was getting an error code for the two circuits being out of sync and that was the only thing I could think of in regards to having to floor the brake pedal to get it to start.

 

Well, in the grand tradition of mystery automotive gremlins, the thing no longer needs any contact with the brake pedal to start. I got nothin' in the way of explanation. On to start tearing into the heater/ac fan and ducts to find the creature that has apparently died in there.

 

Intermittent electrical problems are always the funnest electrical problems.
Good luck with the duct system, hopefully whatever it was was courteous enough to die around the fan where it's easy to get to.

 

That’s probably where you’ll find your issue and is relevant information that should be included in your initial post. You definitely need to read the thread that I linked earlier. There is a mention on rodent activity and damage in it.

 

Sounds almost like you may be the next victim of A-pillar/windshield water leaks into the driver side harnesses and/or fusebox.

 

If it’s a rat I recommend doing a full gut autopsy so you can determine which color wires it ate. And post video of you doing it. You know, for science.