| Author |
Message |
david schirmer (David)
| | Posted on Sunday, September 23, 2001 - 10:08 pm: | |
Here is the promised post about diodes in the lifter motors. I haven't been having any troubles recently but if I do, here is the recipe. BTW Ric, the guy who wrote this, is a pretty knowlegeable guy who contributes to the Ferrari list. (the other site)... David
> Subject: [TECH] Blinking Headlamps (repost of old article)
>
>
> >When I met you in Dallas, we discussed the problem of my left headlight
> >blinking (going down and right back up every few minutes), and you
> >recommended that I replace the diode in the motor. Do you have to take
> >the motor out? Where is the diode and how do I get to it?
>
> Stan is referring to a problem that occurs when one or more diodes
> (rectifiers) in the headlamp lifter motors fails. This can cause problems
> such as "winking" headlamps (one side or both), continuously running
motors
> (up and down), or the lack of synchronization of the left and right
motors.
> Loose or dirty connectors can also cause intermittent running or
"cycling",
> as well. Non-functioning (dead) lifters is either the motor, wiring or the
> associated relay.
>
> The good news is, you can check the diodes in the headlamp lifter motor
> without removing the motors from the car. You'll need a multi-meter (VOM)
> that is capable of checking diodes (preferred) or one that has an low
> resistance Ohms range. Also needed are some screwdrivers and possibly end
> wrenches (10mm) and a low-wattage soldering iron.
>
> This procedure is for 308's, specifically my '81 308 2-valve. Other models
> and/or years may vary, but I think its the same all the way through the
328
> model. GT/4's and 246's may be similar.
>
> 1) Disconnect the battery ground strap.
>
> 2) The headlamp motors connectors (both sides) should be disconnected. You
> probably will need to remove the grill (308's) or cover (328's) above the
> headlamp mechanisms to accomplish this, or, if you're flexible and nimble,
> you may be able to reach it with just the front bonnet up.
>
> 3) Use the hand crank knob on top of the motor to move the headlamp to
about
> the halfway point (i.e. 1/2 up, 1/2 down). No precision is needed, just
> somewhere in between.
>
> 4) Now use the VOM to check the diodes by measuring the conductivity on
the
> BLACK and GREY terminals. Measure with the VOM and then reverse the VOM
> leads and measure again.
>
> If you have a VOM with a diode check feature, in one direction you'll get
> infinity (no reading) and in the other you'll get a low value (usually
less
> than 1.00 V).
>
> If you're using a VOM in Ohms mode, select a low scale range (1-3K ohms).
> In one direction you should get a low reading and in the other a fairly
high
> or infinite reading.
>
> 5) Now check the other diode by measuring, as in step 4, with the BLACK
and
> GREEN+BLACK wires. Note that at this point, both diodes share the BLACK
> wire.
>
> 6) If all is well, you should have made four measurements. Two will show a
> low value and two a high (or infinite) value. If any pair shows low values
> in both directions, the diode is shorted out and needs to be replaced. If
> any pair shows high values in both directions, the diode is "blown" and
> needs to be replaced.
>
> 7) If either diode is bad, you'll need to remove the motor from the car.
> This can be done by removing the drive lever nut and the drive lever and
> then the three bolts that hold the motor to the headlamp lifter assembly.
>
> 8) Peel back the rubber covers on the motor. This can be tough, but it can
> be done. Only the lower cover needs to be removed.
>
> 9) On the lower part of the mechanism, below the motor on the gear
housing,
> you'll find a pair of diode rectifiers (small cylinders, usually black
with
> a white or silver stripe at one end, with two metal leads coming out).
> Using a low-wattage soldering iron (designed for electronics, not
> woodburning) and remove the offending diode. Make sure to note the
> orientation of the diode before removing it. If you don't know which one
is
> which, measure the diodes again with the VOM, this time directly on the
> diodes leads.
>
> 10) Take the dead rectifier to your local friendly electronics parts store
> (Radio Shack or equivalent) and find a similar sized unit from their
stock.
> Exact specs are not really critical as all the part is only used for is to
> rectify a signal to a relay. Find a rectifier with at least a 1 Amp rating
> and a minimum of 50V. A "1N4001" is a good choice.
>
> 11) Put the good rectifier on the motor and perform steps 4-6 again. If
all
> is well, reseal and return the lifter motor to the car.
>
> 12) Reconnect the connectors and the battery ground strap and test. Be
> careful when you reconnect the ground strap, since the half open headlamps
> will most likely cycle back to the resting position... don't be in the way
> when this happens, the car could get scratched or it could bite off your
> fingertips.
>
>
> NOTE: Measure both headlamp lifter motor's diodes. Sometimes, a diode
> failure in one motor can cause the opposite headlamp to act up (no
really).
>
> LEGAL NOTICE: This procedure is "Do-it-yourself" (DIY), and, as such, is
> not approved by Ferrari SpA or Ferrari North America. Performing this
> rather simple check on your OWN car could result in the utter destruction
of
> you car, it's value, and/or Ferrari's worldwide reputation as a whole.
> Mayhem, world domination and lawsuits may ensue. Should this or any other
> self-repair fail, the DIY team will disavow any knowledge of your actions.
> This E-mail will self destruct in 5 seconds....
>
> Ha! Sorry I just had to say it!
>
> Another one for the archives...
> Ric Rainbolt
>
>
> ------------------------------------------------------------
> The Ferrari-Tech List
> Ferrari technical and mechanical related posts ONLY.
>
> |
david schirmer (David)
| | Posted on Wednesday, September 05, 2001 - 2:40 pm: | |
The diode rumor is true. I talked to someone this weekend and he is allegedly going to send me a step by step on how to replace them. We shall see and I will post it if I get it. |
stacy o'blenes (Stacy)
| | Posted on Wednesday, September 05, 2001 - 1:32 pm: | |
David,
I also heard the same rumor about a diode on the headlight motors. The 79 308 gtb I recently purchased has a driver side headlight that when switched off goes down, immediately comes back up and then goes down and stays down. The mechanic who checked the car before I bought it said that it was the diode on the motor that was bad. I don't know anything more about it than that but if you find anything out let me know because I would like to fix mine.
Stacy |
david handa (Davehanda)
| | Posted on Thursday, August 30, 2001 - 6:03 pm: | |
Hopefully someone else knows more about this, but I hear that there are some diodes on or near the lifting motors that can fry. I fyou replace these with the correct values, that can often fix these "winking" headlights. Anyone? |
david schirmer (David)
| | Posted on Wednesday, August 29, 2001 - 10:28 pm: | |
Just a quick report. I checked out the lifting mechanism. There is a motor that turns a crank. It makes half a revolution to lift the headlight and then half a revolution to lower it. There is no outwardly visible limit switch. I had Diane, my lovely assistant, turn the lights on and off. It appeared that the offending headlight was lifting and then lowering ever so slightly before stopping. The crank would turn just a little too far. My assistant reported that she heard the relay click to start and then a double click to end. I fiddled with the manual raising knob to see if that would do anything. It didn't. Diane made sure the relays were seated. We spent some time raising and lowering headlights and all of a sudden they were aligning perfectly. The double click of the relays was quicker than before and everything is working just right. So go figure.
Diane is claiming full credit for the repair. That is the last time I get her to help me! |
david schirmer (David)
| | Posted on Tuesday, August 28, 2001 - 9:17 am: | |
Good thought Peter, I hadn't thought of that possibility. I will check that out. Is there a method to test the relay?
Actually I just thought of the answer. I will swap the left and right lifter relays. Of course with an intermittant problem, the testing takes a while, so if there is a sure fire method I would love to hear it.
David (who should be working right now instead of on FC) |
'75 308 GT4 (Peter)
| | Posted on Tuesday, August 28, 2001 - 3:52 am: | |
Relay coils have copper wire that is finer than human hair.... Can't be fixed.
Is there a limit-microswitch that works on some lever of the headlight bucket? I know my GT4 doesn't have this (just a screw that stops on a tab), but does your 308 have something like this? Maybe it could be striking this switch and sending the headlight back down (?). |
magoo (Magoo)
| | Posted on Tuesday, August 28, 2001 - 12:09 am: | |
David, The relay sounds like the problem. Do not try and fix the old one. Either the points are burned up or the solenoid has gone bad. Pick up the orig. replacement. |
david schirmer (David)
| | Posted on Monday, August 27, 2001 - 11:58 pm: | |
My right headlight has begun to intermittently not raise itself correctly when I turn on the headlights. 1977 308. I suspect that the headlight lifting motor relay is starting to fail. When I turn on the headlights, the right light will raise and lower a few times. When this is happening I hear a clicking in the relay panel area.
My questions. Is my diagnosis correct? Are these relays a pain in the neck to find or can I go to NAPA? (Bosch 332204101 according to the manual) Can a relay be repaired?
Yes, I will replace both the right and the left...
David (still OC after all these years) |
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