It sounds like the same problems I was having. It started out to be very random, then after months, all the time. If you have access to another cluster, try changing it out.

 

I was having the same problem with our 2003 Dodge Caravan: Even with no key in the ignition, the door ajar alarm rang continuously when open, and the dome light stayed on even after all doors closed. I spent several hours searching the internet, found this great site, tried the WD-40 trick, and several other tests. Imagine how dumb I felt when I discovered this evening that the interiour lights adjustment wheel was simply turned up to its top notch, ....which forces the dome light to stay on, .....and my friendly door ajar alarm was simply warning me .... guess what.... not to leave the dome light on when leaving the car! ! I turned it down one notch and now all is well, .....except my ego!

 

The courtesy light on my 1999 F350 would not shut off, as well as the outside cargo light. Couldn't find a solution so I gave up and just removed the light bulbs. A few years later my husband's 2003 Explorer started doing the same thing. My husband tinkered around and finally figured out what the cause was. The dimmer switch on the dash. You can turn it way down, or turn it up for the instruments on the dash to be at their brightest. When the dimmer switch wheel was turned from dimmest to brightest, if we turned it all the way until it "clicked" into the brightest position, this was preventing the courtesy light from turning off. We rolled it back to just before it "clicked" at the brightest positition and we haven't had a problem since. My guess is that when we were cleaning the dash, we accidently rolled the dimmer switch wheel until it clicked.

 

2008 expedition is doing this now. 100,000 miles on it as of 2 weeks ago. it used to do it when i hit a really hard rut in the road, but now, its flickering off/on while driving. i pulled the fuse for the "interior lights" and verified that the dimmer **** wont turn the dome lights on... however...

still looks like a friggin disco show in here....

 

Anyway, problems with door ajar forced me to pull fuse after slamming door on several different occasions. Fuse out / door ajar was messing with alarm, windows, instrument cluster etc. Hit the guilty door this morning with just a couple soaking shots of the REM oil and presto, good as new. Great info, saved me some serious time if not also the cash I would have ended up doling out.

I am off to the next fix (https://www.f150online.com/forums/ar...ay-repair.html), and this post has also proven correct w/ the resistor problem.

Thank you.


2004 F-250, 5.4L, Crew cab, 8' bed

 

https://www.f150online.com/forums/20...int-light.html

 

Thank you, I did just what you suggested and it worked great. Thanks again.

 

I recently bought a '97 Ford Expedition, just as an extra truck to have around. The other night the "door ajar" light just suddenly came on as my wife and I were about to leave our driveway. The interior light did go off after about 10 seconds after we started down the road, but the dash "door ajar" light remained. However when we parked the interior lights remained on. I tried different tricks I read online, I tried this simple WD40 trick and it worked like a charm. What I did find was that it took about three rounds of spray into each door latch. I then let the latches dry out for about 20 or so minutes and then went back out to check. After starting the truck I closed the driver's door and the "door ajar" light went out. I screwed the interior lights back in and sure enough it is all working as it should! Kudos to lees99F150 for posting this!!

 

I have a 2004 Excursion Limited and I had all of the problems that many people have had with lights staying on. I had two door switches that were stuck and needed to be replaced. After the switches were replaced my lights still remained on. The WD-40 trick was not the solution. It all starts with the battery system. Ford does not run a continuous ground wire from the battery to the electric devices. The engineers at Ford use the body as the return path for the circuits. As the vehicles age, corrosion sets in and the path for a complete circuit is lost. Ford uses at least 10 ground points all over the vehicle. The fix is to run a ground from the battery to each ground point thereby eliminating the body ground issues created by corrosion. I have dual batteries and they were not making a ground between them in the engine compartment. I started there and ran common ground joining the batteries then ran a wire through the fire wire into the cab. I cleaned all connections and used star washers as well at each body connection.

The instrument cluster has a microprocessor that controls all of the devices based on the door switch inputs. The outputs are only able to operate properly if the circuit it is controlling is referenced to one common ground. There are two outputs for the light circuits from the cluster. Both operate when the doors open and close and but the other operates the time delay relay. The relay is not the problem, it comes from the cluster not seeing enough load to cause the output to go low causing the relay to stay picked up. The cluster does have a 30 minute battery saver circuit that is a failsafe incase either circuit fails but often times this doesn't work either. I haven't seen any comments even on the Ford dealer Oasis site about poor ground connections. Many of the Ford vehicles use this same wiring scheme so many other Ford cars and trucks probably experience the same issues.


I fixed my issues and the only cost to me was effort, wire, and my time.

 

I also tried the WD-40 trick. It worked for a day or 2 each time I tried it. Replacing the switch in the door is what fixed mine.

 

[QUOTE=lees99f150;1642829]Since people are always asking how to fix their dome light or door ajar light from staying on. I thought i would make a post showing how to fix it.

If the light is on and the doors are shut then spray some WD40 in to the latch. The door switch is probably stuck.
Spray in both doors then open and close them a few times. sometimes you will need to spray a lot of WD40 and it will run out the bottom of the doors. Just leave them open until it drains out.[/QUOTE Awesome Fix!!!! Two quick sprays, open n shut twice, lights went out!!!!! U ROCK!!!!! Thanks......

 

Lee you are a Genius! My 2003 ford f150 has been in the shop three times for this problem and the mechanics were clueless. They replaced the sensors and it did not fix the problem.

After reading your solution it only took 5 minutes for me to fix it, and it has been working flawlessly for months.

Thanks,

David

 

I have been dealing with this problem since the day I bought the truck. Honestly didn't really believe you at first but I thought what the hay and did it just to see and thank you for proving me wrong!

 

As I stated before, it's a great fix, temporarily, until the switch finally fails. The best fix is to just replace the switch. About 1 hour of work and a $17 part.

 

Sometimes its the simple fix.

I have a 2009 F150 XLT Crew-cab. The right rear door ajar warning has been a pain for months!!!

1. Tried the WD-40. No luck.
2. Tried to replace the door ajar switch but found out its built into the door latch mechanism.
3. Replaced the complete door latch mechanism. No luck.
4. Started more diligently checking the wiring between the door and body of the truck. Thought maybe it was a broken wire. No luck.
5. Eureka! The door wiring connector under the boot at the body of the truck was only partially connected. It came apart when I pried the boot off the connector.
6. Re-connected the connector, installed the boot, and re-assembled the door.

Works fine now!

It seems the boot held the connector mostly connected and caused the intermittent issue.