I have a 2003 f150 7700 4x4 with a 5.4l. Lately ive been having alot of electrical issues, sometimes the truck randomly goes into anti-theft mode, sometimes my wipers dont work or randomly come on, my dash lights stay on sometimes, it starts itself with the key just being in accessory mode and the starter stays on even after the engine is running but only in Park or Neutral, when its in gear the starter shuts off.

 

Tripping PATS (anti-theft mode) is common and usually caused by a failed eec power relay. Getting that out of the way in case you have 2 separate failures.

Check for water in your passenger compartment fuse box. It happens when the windshield leaks on the driver's side. If you do any searching, you'll find people contradicting me in the archives saying that all mysterious electrical gremlins come from water in the GEM. I'm here to tell you not to replace the gem until you've actually found water inside it. People replace GEMs all the time when the problem is the fuse box. Water can hit the top of the GEM, which is bolted to the top of the fuse box, and drip down into the fuse box. If you look at any pictures or videos of how the fuse box is put together you'll see how water can cause parts of the fuse box to become "hot" when they are not supposed to be.

 

raysorenson I checked all relays and fuses and they where all good. There have been times when there's water on driverside floor, so there is definitely water leaking in

 

My old 98 had sort of the same symptoms about 12 years ago. Sometimes the starter would crank the engine while washing the truck, just after washing the windshield. No keys in the ignition and it wouldn't start....just crank. At times the power windows wouldn't work and head lights wouldn't shut off with the switch.

The fuse block and GEM under the dash was getting wet. Repaired the leaks, blew out the fuse block w/compressed air. Never another problem.

Hope that helps!

 

Water gets in from the back side where there are 2 huge connectors bolted to it. There usually isn't evidence of water intrusion looking at the fuse and relay side.

 

The female side of the bulkhead connectors will look like this. The water settles down in the bottom, and wreaks havoc. My Expedition would try and start itself..... the starter would turn and turn, and the only way to stop it was to disconnect the battery. I took the GEM/Fuse Panel assembly out and submerged it in dry rice for a day to draw out all of the moisture, sealed up the leaky windshield, and it was good.

 

As of today, I'm not the only one that experienced that ghost cranking with one of these trucks.....haven't seen it mentioned in the past by anyone until today lol. Lots of strange stuff can occur when it gets wet under there.

But yea, if you use compressed air you should notice moisture creeping out from the cracks. Make sure you have dry coming from the compressor, test that against your hand first.

Good Luck!