Truck bed lights turn on and off

You could pull the fuse in the diagram, that should stop it, short term fix. That fuse is hot all the time. There are trouble codes for bed lamp, find the code and post it. Use an obd2 code reader that will work with your vehicle, that reads po codes as well as manufacturer specific codes. The codes I saw were b1 codes. You know, short to voltage--short to ground--open circuit, those type codes. At the moment, I'm thinking ground, In the diagram, the white wire with blue tracer is ground. It either grounds through the bed lamp switch or the cargo circuit/headlamp switch or the wire itself is intermittently shorted to ground/metal service.

I stopped by the dealership and the service advisor said it is probably a bad switch. Has anyone replaced the bed-mounted switch? Is it straight forward or are there some things to watch out for?

I have had the switch changed less than a year ago. Cargo lights and bed LED lights are turning on and off themselves.

My truck is doing the same thing... did you get it fixed ?

I’m having the same Cargo/bed light issue. Did anyone get this fixed?

I have a 2017 that does the same thing. I live in Michigan and mine seems to only do it in the winter when it’s cold outside. Wondered if weather plays a role in this? Dealership has not been helpful, no codes.

I replaced the light switch located in the box and it fixed my issue

I ordered the switch is that an easy install?

Just pop out the old switch and click in the new one.. small flat screwdriver to pop the switch out.

Awesome thank you

Where did you order switch from? Can you give more details on switch/part #?

get the part from your ford dealer oem part # FL3Z9C888B

I have a 2016 F-150. Had the same issue - solution, replace the switch in the box. The switch part number is SW7733 and comes with the trim plate- bought from the dealer. Cost was $30 can. If you run the part number on the switch it tells you it is for a power tailgate and the cost is $57 at the dealer and doesn’t come with a trim plate. Here is the kicker- the SW7733 is the exact same switch and has the same part number. Don’t get screwed- buy the SW7733 part and change it in 5 minutes.

When you say replace the switch in the box, do you mean the bed of the truck or the cab to the left of the steering wheel column?

You want to replace the switch in the box. Pull the left tail light out and then you can reach the switch. It was a very easy fix.

In bed if the truck

Thank you much! I'll give it a try.

Can you please make a video on YouTube about installing the switch? Thank you

Corey I’m trying to change switch out in a ford xlt 2016 , I pull left tail light lens I don’t see a switch to change . Cargo and bed lights come on and off

Thanks for posting that it is the cargo light switch in the box causing the cargo lights to turn on and off by themselves I was having this issue after three frustrating days and a nearly dead battery I read this post and disconnected the box switch and lights stopped flashing, installed a new switch today and all is good, only cost me 30 dollars for the switch no trip to the dealership

I have a 2017 F150 and the LED lights in the bed will not turn on. When I push the switch the Lights beside the brake light on the cab turn off and on with the switch but not the LED lights in the bed. I purchased a new switch for the bed and it did not fix the problem with the bed LED lights. Any suggestions?

GuruPPMHF: Thank you very much. Your post was extremely helpful. I have a 2017 Ford F150 XLT and I ran into this issue with the bed lights turning on and off when the vehicle was off. I stopped by the Ford dealership closest to me and picked up a SW7733 switch and swapped it out and it seemed to fix the problem. Switch was $29.99 Canadian plus tax. I wonder what caused the issue to begin with? The previous owner didn't have a tonneau on it and maybe and water go into it. Now, i'm not a mechanic, but i know my way around tools. Took me 20 minute to swap it out. It was dirty inside where it was wired. I unscrewed and took off the left tail light, Disconnected it and put it to one side. Then the switch is in the bottom hole on the side of the truck. Disconnected the switch and tested the new one before removing old one. Admittedly, it was a bit of a pain to get the old one out, it sort of snaps in with clips. After struggling with it for a few minutes i did end up breaking it to get it out... Plugged in the wire, Put the new switch in.. Tested it.. Worked perfectly. Put the tail light back in and boom.. All done. Thanks again.

How do you get the light to shut off, while waiting for the new switch to arrive? None of the dealerships close by have one. I ordered one, but won't be here for a week.

Pull the switch out of the box and tape up the leads until you get the new switch. The fault is in the switch as it is in the fender and subjected to water, sand, salt, everything.

I have a 2017 XLT, exact same problem you all have described, lights turn on and off when truck is not on, no key in the ignition. Read all the comments, called the local Ford dealer, they had the part in stock (SW7733) for $19.99. I went to pick it up and the guy asked what was going on with the truck. I explained the problem. He told me the part wouldn't fix the issue so he wouldn't sell it to me!! WTH? He told me to spray luboil (WD40) on the door latch and if that didn't work I'd have to have service look at it. AHHH, I see, you won't sell me a $20 part, so eventually I'll have to pay service way more than that to look at it and tell me they'll replace the switch for $100? I don't think so. Ordered it from Rock Auto.

Just started happening to my 2019 F150. Bed, cargo and side view mirror lights keep turning off and on. Like the guy from Michigan said, it seems to be a winter thing. The dealer said they can't look at it for a week but the battery will probably be dead by morning. Lowered the tailgate, removed 2 screws on driver side taillight. Pushed the taillight back (toward the bumper) to release the clips and the taillight came right out. Disconnected the lead to the pressure switch inside and problem solved until I can pick up a replacement tomorrow. $20 for that thing?

I just started having this problem with my 2018 F150,, 25K miles... The bed and puddle lights turning off and on with the engine off... Hitting the lock on the fob seems to clear it for 10 min or so.. I see there are recalls now for the door latch freezing and the power door actuator failure,, both of which I've experienced in the past month due to the temps in West Michigan.. Could either of these also be the cause?

My 2018 XLT was exhibiting these symptoms - high mount stop light, tailgate handle light and cargo box lights going on and off when truck was not started. I You Tubed "how to remove F150 taillight" which is helpful so you don't damage the taillight. Remove the drive side taillight and then you can work the tabs on the box lighting switch to work the switch out. Once the switch was out and disconnected, the lights all stayed on so I decided to jump them out with a piece of wire. I inserted the wire into the connector and the lights went out. I was going to tape the inserted wire to the connector until I can find a replacement switch. In doing so, the wire fell out and the lights stayed off. Not sure exactly why but the lights haven't come back on and all of the lights are functioning. I'll try to get a switch Monday.

Have had the cargo lights on/off symptoms for a year intermittent which caused dead battery a couple times. Checked bed lights and found bed light switch would not turn them on. Switch felt odd/crunchy. Replaced switch with Ford P/N FL3Z-9C888-B bed lights now work, fairly confident this will fix intermittent problem as well since switch is a input to BCM.

Thanks for help, it was switch in bed

Same symptoms and same results. Appreciate all these posts. Replaced cargo light switch and all appears to be working properly. Motorcraft part # SW7733

Same issue with my 2020 Ford F350. Does anyone happen to know if it is the same part number (SW7733) for the 2020 F350? Is the part in the same location (behind the driver side taillight) for the '20 f350? Also, my experience has been that it certainly appears related to moisture (snow/snow dust, rain, car wash, fog, high humidity, etc.) When dry for a long time, it doesn't do the flashing on/off. Did anyone try electrical grease on it, instead of replacing? thanks