Headlight Turn ON automatically While Using Keyless Entry Remote

1994 Lincoln Town car Keyless Entry Remote Issue

1994 Lincoln Town car and I have taken my Town Car to a few mechanic shops, and telling them my story on how my unlock button can turn on my headlights, which in return was interesting to them. They have had no idea at all of what it would be, then they said it was the FOB module. I replaced it and it did the same thing, so now I think it's the BCM instead, along with some time trying to figure out myself what the problem might be. Please help 

Your Vehicle there is no BCM

Unfortunately your 1994 dosnt have a BCM and the problem you are having is to complex to try and diagnose over the internet and thats why you have not received a good answer. I have enclosed a list of all module on your 1994 and as you can see, there is no BCM. This type of problem is going to require hands on to diagnose and repair.

When you say they recommended a FOB module, and that you bought a couple and replaced them, did you replace the RKE (keyless entry module)....which is the computer located inside the vehicle, or did you just replace the keyfob remote? I ask because this does sound like a problem with the module and replacing the remote wouldn't affect this issue. The keyfob remote send a radio signal to the RKE module inside the vehicle which is connected to the power locks, lights, etc.

The module for the keyless entry is located behind the glove box here...


If this is what you replaced, let me know.
If not, then please let me know if you wish to do some electrical testing with a volt/ohmmeter.

Try testing fuse and relays with voltmeter.

So, some of this may seem repetitive or redundant to you, but let's start out with the basics.

Under the hood, please check the following highlighted fuse in the battery junction box. Then check the highlighted fuses in the instrument panel fuse box under the dash. When you check the fuses, you can remove them and visually inspect the metal strip inside to make sure it isn't blown, but I also need you to check for power at both sides of the fuse while it is plugged into the vehicle. To do this, set your meter to DC volts. There should be a setting for AC and for DC voltage. AC does us no good here. It may say DCV or something similar. If the meter has electrical leads that plug in, put the black one in the socket that says COM and the red one in the appropriate spot for DC voltage. If this is confusing, maybe you could upload a picture of the meter, if you're able. They all look a little different.

Once the meter is set up. Take the point of the black lead and hold it on the negative post of the battery. Take the other lead and touch it to the fuses while they are plugged into the fuse panel at the top of them. There are 2 small holes in the plastic where the metal is exposed. You will want to see battery voltage (around 12.5 volts) on the meter when you touch either side of the fuse. Let me know what you come up with.

When checking for power at the fuses in the instrument panel, do so with the key in the ignition and turned to the RUN position. If you find any of these fuses that have voltage at one side and not at the other, replace the fuse and retest.

What I suspect is happening on your vehicle is that there is a poor ground circuit either in the door unlock circuit or for the RKE module. I've gone over some schematics and I think the door unlock ground circuit is more likely. Let's start there if you don't identify a fuse issue above.

We need to locate ground circuits #200 and 203. These will be black wires with a metal eyelet attached to the end of them that are bolted to the body. Ground 200 is at the driver's side of the instrument panel area and 203 is in the same location on the passenger side. You'll need to pop out the kick panels, near where your foot would rest near the body in front of the door on either side to get to the grounds. Make sure the bolts are very tight and there is no sign of corrosion or other damage there. If so, remove the bolt and use a wire brush or some sandpaper to clean both the body and the eyelet on the end of the wire to create a clean surface and then bolt back together securely. In fact, it's probably a good idea to just unbolt and clean these grounds even if they look okay. 

Try the system again after this and see if anything has changed yet. 

Once you've gotten this far, if the system is still acting haywire, we can continue.

Set meter on 20volts.We will be looking for 0-about 13 volts so 20 V range will be perfect.

Most meters will have 2-4 ports near the bottom that will say COM, OHMS, V and ACV,

or something like that.

Do you see some ports where the non-probe end of the wires would go in?

Ok. Black lead into COM

Red lead into VOmA Bat.

Here's a good way to practice. When the meter is set up, touch the black probe to the negative battery post and hold the red one to the battery positive post at the same time. This will measure the voltage of the battery.

You should get a reading between 12 and 13.5 volts.

Locate the highlighted fuse under the hood. Leave the black probe touching the negative battery post and move the red probe to the top of the fuse. Do not remove the fuse from the fuse panel when doing this. On the top of the fuse, there is likely some writing indicating the amperage that the fuse can handle. There will also be 2 holes in the plastic fuse housing with some metal exposed. Touch the red lead to the metal that you can see through the 2 small holes on top of the fuse. You should get very close to the same voltage reading there that you got when you measured right at the battery.

H under the hood is a circuit breaker. If it is the same size as F, try swapping them and see if the symptoms change.

Under the hood, if you cannot reach the probe back to the battery post, and if you do not have a jumper wire available, You will have to find a good ground to use under the dash. Anything shiny and metal that is bolted to the body will do. The studs and nuts that hold the brake pedal to the body are a good place. You can just scratch the area a little with the probe and hold it firmly there.

Yes, it was just the fuse! Everything is working now, interior lights, side panel, unlock button, etc. thank you very much, I wish I could have met you $450.00 earlier for a $10.00 problem.