How To: Fix dimming lights/gauges

[arskiracer]

I am not very good at explaining things but I'll try to make it as understandable as I can...


1) disconnect negative battery.
2) lift car
3) I had to take off my y-pipe to get to the wires, but you may be able to get to them without removing the pipe.
4) unhook all the wires on the alternator (the thick red charge wire that's held on with a nut, the three wire connector, and the single wire connector.)
5) Get out from under the car and from the top of the engine bay, pull those wires up for access.
6) Locate the three wire connector you pulled off the alternator and cut the red wire on that connector (cut the wire about 3 or 4 inches away from the connector side so that you have room to strip and attach a new wire to it.
7) since you cut the red wire, you now have two separate wires. The wire that goes into the engine bay you will not use and should be taped or something. The red short cut wire that comes off the 3 wire harness will need to be stripped.
8) Extend the stripped red wire (with 18 or 16 awg wire) and run it to the red main alternator wire somehow (the one held on with the nut). I don't know if splicing into that wire is a very good idea, but that's what I did and it worked for me. I used silicone glue to seal it and I taped all around the glue.
9) push the wires back down and connect them to the alternator again.
10) hook the y-pipe back up if it was taken off
11) lower the car and reconnect the battery.

I hope that makes more sense. if there are any parts that you don't understand, let me know and I will try to explain better.

Sorry, I am not very strong with automotive terminology.

[arskiracer]

If anyone thinks they can explain this better than I did, please be my guest.

[eurocrisp]

you dont have to use pink wire.



to attach the new splice onto the main power output post, I used a properly sized ring terminal at the end of the wire, and used heat-shrink around it so crap cant get in there and corrode it. There's a boot on the main power line too... I snuk it through there and my terminal lines up perfectly with the 0 gauge wire's terminal. To wrap back up the part of harness I had to separate for slack, I used a piece of that black ribbed tube wire consolidator stuff, and wrapped that with heat shrink Tape. its not sticky, but if you wrap stuff in it and shoot it with the heat gun it melts itself into a casing.

Thank you Adrian for surfacing this fix.

[VHull03]

ok... so what exactly is this doing?? making a better ground for the alternator or what?

[inthelane]

So does this solve the dimming headlights and interior lights problem?? If so, what exactly is wrong and why does this fix it?? Need more info. Thanks

[arskiracer]

"Mercury 1999-2000 Cougar...

Issue: Some vehicles equipped with a V6 engine may exhibit a flickering condition of the headlamp, instrument cluster, radio, and other interior lights during engine start-up and may continue during the first several minutes of engine idle. After several minutes, the flickering will subside but may not completely diminish. This may be caused by excessive electrical resistance in the battery voltage sensing circuit. Vehicle operation is not affected by this condition."

That's the instructions from the Ford TSB (#00-25-6.)

My car had the flickering lights problem really bad all the time warm or cold. Also it did affect my drivability. I'm guessing that's what was causing the case ground to jump around. The ground problem was causing the computer to read the maf voltage incorrectly and it was giving me lots of idle problems.

I haven't checked the case ground because I can't seem to find a decent computer scanner to use, but my car is doing much much better, so I'm guessing this solved the ground issue. Normally that problem wouldn't have affected drivability, but the pro-flow maf I have only reads 3.6 volts at redline at WOT so at idle it hardly reads anything at all. That in combination with the swaying voltage was screwing up my idle.

[ZEXCougar]

I don't know about not affecting performance... Once I hit about 6000 RPM my battery light goes on, all my lights dim, and my car completely loses all accelleration until the gear change. I would think that this is "affecting performance" seeing as how I am losing 500 RPM's on the top end, plus losing valuable time in the period that it takes the car to shift and regain accelleration. So in a quarter mile situation... I would have 3 gear changes in which I lose all accelleration for 3/4 of a second in each gear... Try running a quarter mile and taking your foot off the gas pedal for 2.25 seconds half way down the track. Performance issue? YES! Huge performance issue.

[Seth]

hrmm. i have this problem or so i think. Anyone have pics of this process for us that no nothing about this? (and i do mean nothing).

[eurocrisp]

well... you gotta take the alternator out to do this. It's a fairly hairy job to do just that IMO. you could have a shop perform the whole thing for $120.

I didnt snap any pictures when i did this, but its easy to understand once you have it out in front of you. The little MSPaint diagram will make sense.

You just cut the red wire from the 3 wire plug, splice some extra length on it from the plug side and and route it directly to the 0 gauge (main power output) terminal on the alternator. This red wire is the voltage sensing line. It lets the voltage regulator know what to make the alternator put out. Ford has it so it senses from all the way up at the fuse/relay box, and apparantly a lot of these wires go bad along the way. What this fix is doing is letting the voltage regulator see exactly what the voltage is the alternator is making by bypassing all the unnecessary and unreliable wiring.

This fix has nothing to do with Ground.

[B3NN3TT]

Originally posted by: Neil
well... you gotta take the alternator out to do this.

It is possible to do this without removing the alternator, isn't it? My impression was that you ust unhook all the wires and pull them out through the top of the engine bay. You got all the room in the world...