1978 Mercury Grand Marquis power window repair

1978 Mercury Grand Marquis power window repair

The Grand Marquis hasn’t been driven in a while as the power windows quit working and I really wanted to be able to open the windows while driving, and to be…

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BBISHOPPCM's World says:

I never understood the vacuum-powered door locks in VWs… it just seems
too complicated, when a simple electrically operated servo does the job
just as well, if not better…

BartV1990 says:

Very helpfull video! one question; where can I find de relay for the power
locks? I can’t find them when I tried to install a remote control for the
locks.

retrochad says:

I actually do have a more modern vehicle in addition, it is the 1992 Ford
pickup.

justwolfslife says:

Chad, about the function of that relay. near the end there you are
absolutely correct. it is to save the ignition switch from the added
current of the “power” accessories such as the windows. the power locks are
on a separate circuit because they are meant to be functional with the key
off.

AllAmericanFiveRadio says:

Very good idea to re-locate that relay. It will be interesting to see the
insides of the old one. Part of it maybe turning into carbon.

vwestlife says:

It’s a German thing, I guess — just like Mercedes only having the
passenger side mirror power operated… they figure that since the driver’s
mirror adjuster handle is within easy reach, then what is the point of
adding a motor and switch to adjust it slower and less precisely than you
can do by hand!

kjm1983 says:

Well, the power window relay is there to take the load off the window
switches themselves, not the ignition switch. It takes a lot of amperage to
get those window motors started and if that were routed through those small
window switches, they would burn up quickly. The window switches are
supplied with 12v at a low amperage. Each side of the switch is connected
to the relay, and the relay in turn is connected to the actual window
motors. The theory is just like a starter solenoid.

vwestlife says:

This is why I prefer manual windows. 🙂 My Mazda3 even has a mechanical
trunk release. My VW has vacuum operated power door locks, but it has an
electric motor to produce the vacuum. Older Mercedes cars had a mechanical
vacuum pump driven by the engine to run their power locks, which meant you
could only operate the locks a few times after shutting off the engine
before the vacuum would be depleted.

Madness832 says:

My God, I remember those foot-operated high-beam switches!

kjm1983 says:

The relay gets 2 inputs from each window switch, depending on which
direction it is pushed, and 2 outputs to each window motor to determine
which direction the motor turns. The switches themselves are not grounded,
but the motors are.

retrochad says:

It seems like on the older cars (pre 70’s) that there was more use of
vacuum to operate accessories. Many cars had vacuum operated windshield
wiper motors but by the 70’s electric wipers became the standard. You would
think though that by now almost all accessories would be electric.

AG3304 says:

What a nasty place to put a relay!Good job!

raymondleeleggs says:

Power windows and powered trunk release equals Rube Goldberg device.

wilkes85 says:

Have you considered just doing away with the relay altogether, so you can
use the windows without having the key in the ignition? or would that
slowly drain the battery? It’s good you found the problem, and now you can
restore your radio! I seem to remember you mentioned one of the channels
were dead. And maybe some new speakers too.

retrochad says:

Actually in this case I don’t think this is how it works…there is heavy
gauge wire going to the power window switch panel in the door, and looking
at the schematic diagram the relay is a single pole type which is energized
whenever the ignition switch is in the run or accessory position. It is
listed as the “power window safety relay” in the schematic and bypassing
its contacts with an alligator clip lead allows all of the power window
functions to work.

TheTarrMan says:

I love old TV’s

AllAmericanFiveRadio says:

Another amazing project. Great demo on using a test lamp. It is remarkable
how effective this simple tool is for troubleshooting problems like this
one. You can get a nice visual of the short and the amount immediately.
Used test lamps a lot in relay phone switching equipment. Nice add-on
projects too. It will be great to have that radio restored. They have
interesting noise circuits.

retrochad says:

Yes you’re right…I noticed that the lamp didn’t glow as brightly as a
“dead short” but the overload was more than 20 amps (enough to blow the
fuse) so I figured it was some component with a partial short. It may be
that the enamel insulation burned through on the relay coil…the relay is
active whenever the car is running. I just found another relay at Autozone
but will re-locate it to under the dashboard so in case there is a problem
again the relay will be much easier to replace.

exodia333 says:

Im glad your not throwing that car in the junkyard we need more cars like
this on the road and nice philco radio brother

naterade21 says:

u should clean ur lens chad

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