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Old 02-19-2002, 12:21 PM
WRS WRS is offline
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Join Date: Feb 2002
Location: Herndon, VA
Posts: 24
Rear Headrest Switch / Relay?


The rear headrests on my '94 e320 stopped falling when I pushed the button. So I popped up the rear seat and tested the vaccuum. The vaccuum checked good (when I bypassed the relay / switch the headrests fell). So I took off the electrical connection from the dash switch and decided to test the voltages on the pins to see if the dash switch or the relay was to blame.

I measured all pins to chassis ground. I got 11.8 volts on the pin with the black / green wire. Every other pin measured 0 volts. Nothing happend when I pressed the dash switch. I'm guessing the dash switch is bad, but would like to remove it from the panel to test it individually before I spend money on a new one.

What is the best way to remove this switch from the dashboard w/o damaging the dash? I'm guessing this is a PBNO type switch, am I correct? If someone could send me the proper voltages and normal switch operation information, I would be most appreciative.

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Old 02-19-2002, 02:33 PM
MikeM's Avatar
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Join Date: Apr 1999
Location: Cincinnati, OH, USofA
Posts: 135
Try this,

While moving, accelerate a little, and while releasing the throttle, hold down on the switch. You might find they drop. If so maybe not enough vacumn is present

I doubt the switch is bad unless you have depressed it over 10,000 times.
Mike Mullins
97 E320
90 944/S2 Cabriolet
94 Toyota Pickem up
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Old 02-19-2002, 03:27 PM
WRS WRS is offline
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Join Date: Feb 2002
Location: Herndon, VA
Posts: 24
Hi Mike,

I tried that in an attempt to build up the vaccuum pressure, but still no go.

I'm convinced it's electrical / mechanical since when I connect the vaccuum lines directly (bypassing the relay valve) the headrests drop with no problem.

I don't have the manuals, so I can't tell what contacts of the relay need power to open the valve. If I knew that, I could test the electrics to tell if it is the switch or the valve. Also, if I could get the switch out, I could short the contacts manually to bypass the switch and see if the switch is at fault.

How do I safely get the switches out of the dashboard?

Thanks for the help.
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