I have a '99 xlt 3.0L flex 4x4, and have a parasitic draw, where the battery will be completely dead overnight. Have used a multimeter and have been able to isolate the issue to fuse #35. I pulled the fuse and let the truck sit for 2 days, and was still able to crank it over. As far as my information goes, this fuse is for either RABS, or parking lamp/trailer lights but if I pull the fuse, my truck will not start. So my question to the forum is, does this fuse power anything else??

 

Well, according to the owner's manual, fuse #35 in the driver's side box powers only the parking lamp circuit and the towing light relay, neither of which should inhibit the vehicle's ability to start.

I have the same make, model, and drivetrain, and pulled fuse 35, only to find it did effectively nothing in my scenario, which leads me to believe that fuse 35 is strictly for the towing circuitry, of which I have none so moot point.

All that information together means your problem lies elsewhere. But first we need to answer before we go any further? Is it a crank - no start or a no crank no start?

If it is a crank no start then the starter can rotate the engine, but it doesn't sucessfully start. If it is a no crankno start, then all you hear is a loud click, if anything, and the engine is NOT turning. This makes a big difference.

 

The engine will crank, but not start, if the engine is cold. If the engine is warm, it will start, but runs rough, and the throttle doesn't work. Also, when I shut the engine off, if you walk towards the rear of the truck, you can hear a faint high pitched whine, but I'm not able to tell exactly where it is coming from. And when I pull the fuse, that whine goes away as well

 

Strange. The fact it won't start when it's cold sounds like the mass airflow sensor to me. As for the throttle not working, when you step on the accelerator pedal, the throttle body plate does not move?

About the whining noise, it sounds like an electrical thing to me. However, there's nothing stock at the rear of the truck that is capable be making a whining sound, especially correlating to whether or not fuse 35 is in or out.

A lot of times, electrical issues (esspecially the really strange ones) come about when people modify things. So, I ask, has the vehicle ever been modified in any way, to your knowledge?

And also, does it have the towing package? If it does, you should have a reese hitch and a flat four plug somewhere close by the hitch. running into the factory harness.

 

As far as I know, there haven't been any modifications done to the truck and it didn't come with a towing package. No hitch or electrical connector.

And when you press the accelerator peddle, the plate does move. With my limited knowledge of cars, my first thought was it could be the fuel pump (because of the winning noise) but I'm not sue of the location of the fuel pump

 

Ah, you reminded me of the fuel pump. Technically the fuel pump does make something similar to a whining sound, heard for two seconds when you initially turn the key on engine on or off, but with the key off the pump shouldn't receive any power. The fuel pump is located inside the gas tank and to replace it, either the bed must be removed or the gas tank must be dropped.

Since you have no towing package, having fuse 35 installed does effectively nothing. I tested it on mine and it makes no difference whether it's in or out. Turn signals front and rear, parking lamps front and rear all work. So, in reality you can simply leave it out.

Here's a test. With fuse 35 installed, turn the key on but don't start the engine. You should hear the fuel pump run for two seconds. The actual fuel pump relay is #9 in the mass distribution box under the hood.

If you hear the pump, then remove fuse 35 and try again. If you do not hear the fuel pump with fuse 35 removed, some wires have been seriously crossed. It's a longshot, but that will certainly tell you why the truck won't start with the fuse removed.

 

Thanks for the advice. I will definitely give that a try, and post the results, but unfortunately won't be able to until this weekend