Need help Electrical on Lincoln

[Tyghe Williams]

Problem: when I push switch for door locks the lights come on while switch is engaged and door locks don't necessarily activate (low power to locks).

Caused originally by rain water through window shorting out the electric mirror adjustment switch (Totally Fried!!!)

Car: 1994 Lincoln TC

Tried to trace for short... but no luck yet.
All fuses are good under hood and dash that I can tell.

Any help ?///
Ty

[sierrap615]

just basic electrical checks - check voltage drop of switch and locks. check for current draw of locks. anything abnormally low is an electrical problem, anything abnormally high is an mechincal problem

[curtis73]

Double and triple check all grounds. When you say water damage, shorts, and corrosion, I think GROUNDS. When a ground is bad, it finds its way through other things. since your interior lights are ground-activated, it makes sense that it grounds through them.

[Tyghe Williams]

Originally Posted by curtis73

Double and triple check all grounds. When you say water damage, shorts, and corrosion, I think GROUNDS. When a ground is bad, it finds its way through other things. since your interior lights are ground-activated, it makes sense that it grounds through them.

I should have said the "headlights" come on ... inaddition the interior lights are out completely and the automatic climate control works , but I now have to manually turn "On" to "Automatic" from "Off"vs. the original Auto "on" position

[Tyghe Williams]

Originally Posted by curtis73

Double and triple check all grounds. When you say water damage, shorts, and corrosion, I think GROUNDS. When a ground is bad, it finds its way through other things. since your interior lights are ground-activated, it makes sense that it grounds through them.

And... a Stupid question is... what do you mean by a "Bad ground"

How to detect, and cure?

[curtis73]

Everything electrical in your car recieves positive power via a wire, but the negative returns through the frame/body. The negative on the battery is just connected to the body and frame (called the ground). The returning juice is carried to the battery by the car itself. A good example; your interior lights always have positive power to the bulb. When you open the door, the door pin connects the negative wire to the body (grounds it) and the lights come on.

To find grounds follow the suspected wires back until you see them terminate at a screw in the body. If there is any corrosion or junk around it, its not properly grounded. Cures are to remove, clean with an abrasive or solvent, and reinstall.

When there is a bad ground on something and you activate it (like your power locks), the power still tries to get back to the battery. Since there are other things in the car grounded (like your headlights) chances are its leaking backwards through other items to make it back to the battery.

The cure is to make sure you have no shorts, bare wires, and the grounds need to be perfect.

[Tyghe Williams]

Originally Posted by curtis73

Everything electrical in your car recieves positive power via a wire, but the negative returns through the frame/body. The negative on the battery is just connected to the body and frame (called the ground). The returning juice is carried to the battery by the car itself. A good example; your interior lights always have positive power to the bulb. When you open the door, the door pin connects the negative wire to the body (grounds it) and the lights come on.

To find grounds follow the suspected wires back until you see them terminate at a screw in the body. If there is any corrosion or junk around it, its not properly grounded. Cures are to remove, clean with an abrasive or solvent, and reinstall.

When there is a bad ground on something and you activate it (like your power locks), the power still tries to get back to the battery. Since there are other things in the car grounded (like your headlights) chances are its leaking backwards through other items to make it back to the battery.

The cure is to make sure you have no shorts, bare wires, and the grounds need to be perfect.

Thanks for the Explaination !!! The backwards part is always confussing , but makes sense... seems like a melt down somewher would be most likely.
Ty

[Tyghe Williams]

Well, now I do feel stupid...!

I had previously checked and rechecked the fuses... both under the hood and under the dash. All appeared ok.

However, after the advice to recheck and triple check for bad grounds, I got to thinking that this just doesn't make sense that the wiring would get hot enough to create a short ( burn thru insulation etc) without blowing a fuse.

But, I first continued down the pat of looking for a short and tracing back from the most logical points (burnt out mirror switch) to find a bad ground.

After, another 30 minutes of this, I decided to recheck the fuses and re read the cars manual for fuse layout and ID. I rechecked all of the most logical fuses once again. All were ok and I even replaced as a i went to make sure they were good.

After still being determined to find this problem, I reviewed the list of fuses again, and decided to try one of the last fuses listed that didn't label the interior dome lights / reading lights ( as such as did another fuse) but as convienence lighting and mirrors etc vs the #5 fuse "heated mirrors".

this fuse #17, was infact blown although vry slightly, still blown., Once replaced everything came on that was supposed to... ie: chimes, interior "convenience" lighting, the door locks now were fully functional and the headlights now don't come on, and the entry acess lighting and entry access ( pushbutton system ) works, as does the AC Climate Control memory and the Radio volume memory.

So now I can reassble the door, the rocker panel electrical conduit, interior trim at front and rear of the door jamb.

Well, it was a learning experience... as to just how sure we are that a problem "must be difficult" when in fact most all repairs are in the end a very simple matter.

As another example, had i known that you can weld the aluminum engine block after throwing a rod .... i could have saved major dollors on repairing rather than replacing teh engine in the same car several years ago.

Thanks for everyone's help... it always serves as engouragement to conyinue even when uyou have overlooked the very basic cause sometimes...

thanks again !!!!!!
Ty

[ccs149]

I have a very similiar problem on the same make and model... 94 Towncar...Out of the blue, the keyless entry, courtesy light, door locks, mirrors, climate control, etc, just stopped working. I checked the fuses and saw that fuse # 17 was blown. Inserted a new fuse and within seconds, it blew. Tried another and it blew. I noticed as well that when you push the door lock switch, the headlights flash on. I removed the door panels and disconnected all the power door lock switches, tried another fuse and it blew as well. Disconnected the mirror switch tried another fuse and it blew. There are seven different things that run off this fuse. Is there a good method I can use to narrow it down to the system that is causing the problem? Thanks...

[Selectron]

Do you have a soldering iron, or know somebody who does? If so then I'd suggest making a test lamp as shown below. Take a blown fuse (it won't work with a good one) and file away the corners so the blades are exposed. Then solder the leads of a 12V inspection lamp to the blades, or you could just use a spare tail lamp bulb, dome lamp bulb etc. and solder a couple of leads directly onto the terminals of the bulb, then wrap the bulb base in insulating tape so it won't short against anything. The lamp wattage isn't critical - I'd probably use something around 10W or less.

Insert the lamp into the fuse socket and it will illuminate - then start disconnecting the items fed off that fuse, and when you disconnect the circuit containing the short-circuit, the lamp will go off, or perhaps remain lit but only dimly. Then you can unplug your tester and start fault-finding on the circuit which you've now identified. When you think the fault is fixed, reconnect the circuit but instead of putting a new fuse in, plug your tester in instead to verify that the short has indeed gone, and that saves wasting good fuses.

The other alternative, if you have a multimeter, would be to measure the resistance from the output side of the fuse socket, to ground - that will reveal the short-circuit and then you can unplug items until it clears. To do that, first measure the voltage at the fuse socket - set the meter to a suitable DC voltage range and connect the black lead to ground and then, with the red lead, probe both sides of the fuse socket - one side will show 12V and the other side will show 0V - it's that 0V side that you're interested in. Next, switch the meter to the resistance (ohms) range and touch the meter leads together - you should see a reading of around 0.5 ohms. Then connect the black lead to ground and the red lead to the dead (0V) side of the fuse socket - you should see the same reading of 0.5 ohms, or perhaps somewhat higher if it isn't a dead-short. Then start disconnecting items fed from that fuse and go back and check the resistance again after each disconnection to see if the short has been removed.

I'm in the UK so I'm not familiar with your vehicle because we don't have them here so I can't offer any specific help, but I'm an electronics engineer so I can help out with any general electronic/electrical questions which you might have, so let me know if you don't follow any of that. Good luck.

[ccs149]

Finally got a chance to try out your test. Plugged in the blown fuse with bulb and have now unplugged every component in all four doors. So far no luck. The bulb stays on. Need help on where the keyless remote module is located? Also when you press the door lock switches to the unlock postion, the headlights STILL flash on and I hear a click coming from under the dash??

[Selectron]

I was looking at the Lincoln forum here on Automotiveforums and there's an old post describing what would seem to be the exact same problem that you have. It doesn't say what the resolution was but there's a useful-looking link in the reply.

http://www.automotiveforums.com/vbul...d.php?t=537059