Faulty door ajar light/chime
 

Hi All,

I'm having an issue with my drivers side open sensor chiming all the time. If I hit a bump while driving down the road the open door chime goes off, If I go around a right hand corner the chime goes off. While sitting in the drivers seat, if I push lightly on my door with my left elbow the chime goes off.

I've spent lots of time searching Google and the most common fix I read about is to liberally spray WD40 into the door latch and then open and close the door several times. I've done that countless times with no luck. I also read that it could be caused by a faulty open door sensor located on the bottom of the door latch assembly, so I ordered a new sensor and went through the process of taking off my door skin and replacing the sensor, but that didn't fix the issue either. Other's have suggested to just disable the chime, but if at all possible I would rather just fix the issue.

Does anyone here have any ideas of what I should be looking for?

Thank you in advance for any help you can offer.

Cheers,
Justnacre

Welcome to the forum

The door latch sensor is a GROUND when door is open, no ground when door is closed
So unplug the 2 wire connector and that will remove the ground, see if light and chime still come on
If light and chime still come on then either the wire is shorted to ground some where or its ANOTHER door that's the issue

What year is the Ranger?
And its is a 2 door or 4 door model?

Assuming 1995-2003, the GEM module, behind the Radio, operates the door ajar light and the chime
If it detects a GROUND from a door sensor it activates the light and chime

If you tell me the year I can tell you the wire colors to check

Hi RonD,

I appreciate you taking the time to respond to my post. My Ranger is a 2008 XLT 4.0L 4DR Supercab

Let me apologize in advance if if any of the questions I ask seem obvious to you. I'm not a mechanic so I don't want to make any incorrect assumptions. So, when you say unplug the 2 wire connector, do you mean from the door ajar sensor located at the bottom of the door latch assembly? If so, I know that the chime/dome light still comes on with that unplugged. When I replaced the sensor a few days ago I noticed that the chime and door open light (on the dash) was still on.

Your comment about it possibly being another door has me wondering because originally I thought it was the rear drivers side door. You see, the lower door latch striker (here's a link to what I'm talking about) on the drivers side rear door has rusted a fair bit which allows a little bit of wiggle in the door, even when I slam the rear door shut. But I had previously removed the rear door skin and tested the sensor and it was fine, which is why I thought it must be the door ajar sensor on the front driver's side door.

Do you think that the rusted lower door latch striker and that little bit of wiggle room could be what's causing the issue?

Thanks again for the help!

Cheers,
Justnacre

2008 Ranger will be different, but same principles in that the door switches send back a GROUND to the SJB when a door is open
SJB = smart junction box, it replaced the GEM module in 2004 and up Ranger, SJB is part of cab fuse box, behind the passenger side kick panel

Yes, I mean unplug the door sensor's 2 wire connection

If in doubt about a door sensor just unplug it, that its "Door closed" state, no ground, when the 2 wires are connected together, thats "door open" state

You can unplug all 4 door sensors, if you still have light and chime then problem can be a short to ground on a door sensor/SJB wire or in the SJB itself

You can use an OHM meter on the two wires, key OFF
Set meter to 200 ohms, touch the 2 probes together, you should see 0 ohms in the display, that means its a short between the 2 probes, so now put one probe on one of the sensor wires and the other probe on the other wire
If you find a door's sensor wire pair with 0 ohms, or under 20 ohms, then you found the wires with the short, but hard to find where its shorted

After testing all 4 pairs and there is no short then problem will be in the SJB

The SJB doesn't have any user serviceable parts for the most part
Its location can allow it to get wet if there is a leak in the windshield gasket, this can corrode the connectors/wires on it
So you will need to remove all the SJB connectors and inspect them for corrosion

Now the fact that "hitting a bump" can cause the light and chime, I would suspect a door sensor/wire issue not an SJB issue

Thanks RonD!!

I'll report back once I've test all 4 sensors.

Cheers!

Driver door dome light doesn’t come on, passenger door work fine
 

Dome light will not cone on, when it open, passenger door work fine