Howdy all,

I searched all around the net and couldn't find the answer I'm looking for.

I picked up a 1995 Ranger XLT 4x4 a few weekends back for a steal of a deal. However, it seems that one (or all!) of the owners cut some corners maintenance/repair wise. Frustrating as it is, for every step forward I take, I seem to take one to the left and two backwards! Currently I've spent several days diagnosing the dreaded "Door Ajar" light in the dash. When I bought the truck there was black electrical tape over the light on the cluster and the dome light itself was removed, so the problem must have been around for quite some time, annoying the previous owner. I figured this was his quick fix.

Wanting to make the truck right, I tried the WD-40 in the door jamb trick, but unfortunately this did not work. I then replaced both door sensors, hoping that this would solve the problem, but it did not! Finally, I jumped the connector at the sensor, with the sensor unplugged, completing the circuit. The light stayed on though!

I then unplugged the ton connector plug to going into the GEM behind the radio - this turned the light off, but I also lost control of my wipers (and possibly more). I also noticed that my truck doesn't chime/beep/buzz/notify me at all, nor is there any audio signal that the lights have been left on with the ignition off/door open. I opened the GEM, and the buzzer is still in place (read that some people remove these).

Finally, I tried to see if there was maybe a short in the harness going from the doors to the GEM. Using the cigarette lighter as a + signal, I connected the other lead of a multi meter to the wires of the GEM connector for the door ajar signal (gray/red and yellow/black, if I remember correctly). Both are reading ~5v with the truck on, doors open or closed, indicating that wire is grounded.

Another thing... I pulled a dome light from a junkyard out of an Explorer and installed it, though the map lights work but the dome light does not! Even with the "door ajar" indicator on, the dome light will not come on, doors open or closed.

So I guess my questions are this - where should I go from here? I would presume that the wires grounding/completing the circuit would indicate that the sensors are not the problem.
Additionally, what could cause the truck to stop chiming/indicating the doors are open, or the headlights are on?

Could this be a faulty GEM? I don't know what else to think, with the given symptoms, but don't want to spring for an expensive unit that ultimately doesn't fix anything.

Thanks guys, and cheers!

 

Did a little bit more playing, and with disconecting the door ajar sensor switch inside the door, both sides of the plugs are grounding on both doors.

Now I'm not sure how the sensor operates, whether it completes the circuit for an open door (grounding both wires), or if closes the circuit for an open door (leaving one wire grounded, the other not).

I do find it highly unlikely that BOTH drivers and passengers doors would have shorts in the wiring, for just those wires, at the same time. Occam's razor, right? However, I don't know what else it could be...

 

Guy I feel for you cause I have kind of opposite problem, that whenever drivers door is open the chimes are on without key . Checked ignition cylinder and tabs and tried spraying wd40 on door jams and still no luck. It does go off when key turned to check engine and buzzes and quits. Wish they just left the damn push down buttons in door frame, cause no one here seems to know anything.

 

A little update to my situation.

I unplugged the wiring from the doors where the harness enters the cabin, and also disconnected the door ajar sensors inside the doors themselves, and finally disconnected the GEM behind the radio. This isolated the wiring for the door ajar sensors into three separate categories: door internals, dash wiring, and the GEM. I then connected one lead of my multimeter to a 12v source, and confirmed that both door internals and dash wiring were NOT grounding out. However, even with the plug disconnected, the GEM was reading 10.5 volts at the GEM for the pins that go to the door ajar sensors.

This tells me most likely I have a faulty GEM which is sending a ground to the sensors CONSTANTLY. These are pricey, so for the time being I pulled the bulb from the instrument cluster and added purchasing a new GEM at some point in the future.

 

To anyone finding this in the future, the fault was indeed a faulty GEM. I replaced it with another one I sourced from eBay, and now the door ajar light is out when all doors are closed, and comes on properly, as well as the dome light, when one or more is open. Additionally, it now chimes when the headlights are on with the key out, and when a door is open! Rejoice.