My auto dim brights have been acting up for a while, and now its gotten worse. It went from not dimming, or dimming and not coming back on, to now flashing the brights at oncoming traffic. Anybody know if its the switch, or the sensor behind the mirror, that's faulty?
I had to fix this same problem in my '88 Bird. The sensor behind the mirror controls the auto-dim.
Disconnect the electrical connector going into the sensor behind the mirror. Get a paper clip and jump pins 1&4 (first and last pin in the connector). If everything works normal again, then the Auto-Dim sensor is faulty. Replace it and all will be well again.
Are your headlights flashing completely off and then back on?
sometimes, it works perfectly fine...even to the point where it will keep the lights off if there's another car in the close distance, to avoid turning them on and then off again quickly...but other times they will turn right off and ill have to play with the dial to get them back on, or they wont dim at all and ill have to do it manually. On rare occasions, like the other day, they'll flash frantically; once was at oncoming traffic, the other was when i was turning a corner under a streetlamp.
Classic Auto-Dim flakyness. Replace the sensor, or bypass it like I said earlier, by disconnecting the harness, and jumping pins 1&4. If the Auto-Lamp sensor was going out, your lights would flash completely off and on, and not just flash dim to bright. The auto-dim sensor is easy to replace, takes all of 3 minutes.
I don't even use it. My 88 has it, but I learned 10 years ago when i had my 87 that AutoDim was just unusable. Try driving through town at night after the lights switch to flashing yellow.
I actually missed the second portion to your post earlier lol. Im not electrical savvy, what would connecting the 2 pins do? If the wire wasnt plugged into the sensor, wouldnt the auto dim not work at all?
No, but that is the point here though. Once you bypass the sensor and everything works again, albeit manually, you know for a fact that the sensor is at fault, and not the auto-dim/lamp control or multifunction switch itself. If you just unplug the electrical connector to the AD sensor without jumping pins 1&4 then your brights won't stay engaged anymore, once you jump the pins your brights will work again manually (controlled thorough the MF switch lever on the column, like always). You can keep it like this and control your brights yourself, or buy a new sensor and install it if you like the auto-dim feature. I really didn't need it, and choose to delete it from my bird, along with auto-lamp.
Ok, ill try that. I was thinking it may have been something wrong with the switch, as in the sensitivity adjustment wasn't working, because sometimes I could fix the problem by rolling the sensitivity back and forth.
It's a known issue, and is pretty much always the sensor with these cars. In fact I'd bet 10:1 it's the sensor. I've fixed many in 80's Mark VII's, Versailles, Cats, and Birds at the resto shop I work in on the weekends. Anytime one comes in with that problem, I know automatically to throw an AD sensor at it. Works Every Time.
thats too funny,,
so what does a flashing yellow and flashing red mean??????? (see tysons corner northern virginia in the wee hours of the morning)
The officer asked me that question and my response was "broke"
he kinda looked at me and asked me where i was from and what my lights look like down there in West Virginia,,
I said there are none... he said get out of here,,, just be warned a flashing yellow and flashing red means to "stop with caution",,, I almost pissed him off when i looked him dead straight faced and asked "but how else do you execute a proper stop, would the opposite mean skidding to a stop?"
I didn't think anyone actually used that option. I never use mine since whenever I drive by a new (reflective) road sign my own headlights would set it off.
I almost never use my brights.
When I did pizza delivery, I used the autolamp functiom because I would sometimes forget to turn off my headlamps. Eventally, I got so annoyed with the lights turning on under overpasses and people telling me I left my headlights on, that I just turned it off and forgot about it.
I've had that happen with mine. Really sucks when driving down a dark road. I use autolamp all the time though. The autodim? Not so much.
:iagree:
I use all the features
I love them
I do as well. Except Autodim. I make sure everything on my Thunderbird works. Things that don't irritate the hell out of me.
restarting a dead post, but...I just switched my original auto dim sensor for another one, and now the auto dim does not work at all. If i put my brights on and flip the dial on, the brights do not dim at all for any light. the switch wheel feels looser than the wheel for the auto lamp, leading me to believe maybe the thing the wheel is supposed to be adjusting has come undone?
I also don't understand what the people were saying earlier in this thread about 'bypassing' the sensor. My headlights are not affected at all by the auto dim. If I turn it on, it just dims the brights, it doesn't shut off my headlights completely. Rather than bypasing, it, couldn't you just turn the switch off???
Situation report today...i tried the auto dim and it dimmed the brights, i suppose because it was still daylight out. I covered the sensor with my hand, but the brghts did not come on. 3 hours later, when it was dark, i tried it again, and it still had the brights dimmed, but this time they came back on when i put my hand over the sensor. This is leading me to believe it works when it wants to, perhaps a bad connection.
pay attention to your surroundings when you test again at night.
a near by dusk to dawn light may keep the hi's off.
you are putting your hand over the mirror sensor, correct?
if it switched when you used your hand, then its saying "now its ok to power hi beams".
it tells me there is a light near by keeping dim enabled.
the thumbwheel needs to be operational otherwise is resistance it builds will not trigger the sensor correctly so yes if the wheel feels odd, swap to another.
This system is hard to work on with any light around and getting it to work in the daytime is a pain no matter how well you cover things up.
first the main headlamp switch needs to be off
next the auto lamp and auto dim thumbwheels need to be on only to the point where they both click to the on position.
then the sensor in the dash needs zero darkness for a period of time before it trips the relays to power on the headlamps.
next the mirror sensor needs no on coming light bulbshiznitting it in order to trigger the high beam relay.
ive learned not to troubleshoot this until its dark outside, then i put the car in the garage... i turn out the garage lights and that simulates perfect darkeness.
I even had trouble getting the high beams to come on once because i had a tool on the wall that was chrome and it reflected back to the mirror sensor, that in turn simulated a set of lights coming back to the mirror sensor. I had to throw a tarp over the wall to get rid of reflections.
tricky i know but wait till dark.
i have several schematics of this circuit posted in electrical tech and modified ones as well.
i can now safely say, it works when it wants to. The other night, it was dark out, i was driving in town, the auto dim was working, dimming the brights for every steetlamp i hit, and whatnot. then i parked the car, and came back 2 hours later to drive home. Didn't work at all. If that sounds like symptoms of a bad connection in a switch, then yes, time to ask 50 people on here if they have one for sale.
Its a bit tricky when it DOES work, but i think that's just the way it was designed. For example, sometimes it will dim them when an oncoming car is 200 feet away, and sometimes it will dim them when its 50 feet away. Sometimes it dims for streetlamps, sometimes it doesn't. sometimes when i have the wheel set to a certain position, it wont work, and another position, it will. It's gotten that everytime i use it, i have to have my hand ready on the switch ready to turn them off manually for oncoming, incase the auto doesn't work.
You mentioned modified system, how do you modify it?
I've got a spare set of autolamp/autodim wheels. Expensive to ship to Canada, though, probably at least as much as the part is worth. A USPS small flat rate box is 19.95 with nothing in it.
gotta ask vefore i have you do a test...
are you familiar with a meter and how to use it?
if not either way we can coach you step by step.
i want to test a couple points on the small connector going into the mirror sensor