Door locks stopped working, backup sensor stopped working and engine light on

Hello, Electrical diagnosis is one of the most difficult things to do, especially with issues that aren't necessarily related. Start with the easiest stuff, check the interior fuses and those at the junction box (driver side fender, behind air filter), check the battery cables and another other visible grounds. If it isn't one of those, you'll want to ring up a shop and have them take a look at it. http://repairpal.com/ford-within-10-miles-of-pascoag-rhode-island-02859

i think i know what's wrong with the door locks,i had the same problem on my 2000 F150 and i fixed them by taking the actuators out of the doors,popped them apart,cleaned everything up,fixed them with a very small piece of tin foil! there is a small piece of metal inside the actuator,this is where i put the foil(i just wrapped it a little).what has happened is that over time the little gremlins lose their resistance,the tin foil makes them work again like they are on steroids! now,you will read where folks say OH,that won't work? WELL,it's been 5 years and mine are still on steroids! my truck and your Excursion takes the same exact actuators.now,how they stay together after popping them apart carefully and cleaning and putting back together is by a zip tie/tie wrap(hey,it works),or you can just buy all new ones for bout $50.00 each times 5 at local parts stores.i'm sending you a link on the F150,look at pictures and search youtube for Excursion fix if you gonna fix em.. How To Fix Failing and Sluggish Ford F-150 Power Door Locks www.fordf150.net › Tech Articles Inoperative Door Locks Due to Resistance in Circuit on Ford Excursion Problem Description and Possible Solution One or more of the door locks may become inoperative due to resistance in the circuit. In some cases, replacement of all actuators will be required to correct this issue. Problem Data RepairPal Verified Average mileage: 114,124 (24,000–178,000) 6 model years affected: 2000, 2001, 2002, 2003, 2004, 2005 TEST fuse(s) with a test light for the back up problem..