# Basic question (I think)

Discussion in 'Electronic Repair' started by T Hakemack, Dec 27, 2005.

1. ### T HakemackGuest

I'm wanting to replace a soleniod in a seat belt system with a resistor. The
soleniod has 56 ohms resistance, 12 volts dc, and draws .237 amps.

Can I put a 56 ohm 3 watt resistor in its place or am I totally out in left
field?

TIA Tom

2. ### Mr FixitGuest

perhaps he has a death wish

3. ### Sam GoldwasserGuest

The load is the same but why are you doing it?

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4. ### Set SquareGuest

In an earlier contribution to this discussion,
[That would actually require 13.27 volts into 56 ohms]

Power = V^2 / R - so a 56 ohm resistor across 12v will dissipate 144/56 =
2.57 watts.

However, if it's going in a car, it will be running at 14v or more when the
alternator is charging - and 14^2 / 56 = 3.5 watts - so 3 could be a bit
marginal.

5. ### T HakemackGuest

Thanks, I chose a 5 watt just to be safe. Glad I did, didn't think about the
actual voltage.

6. ### James SweetGuest

Why put a resistor in there though? If the solenoid is bad why not just
leave it disconnected, or replace the solenoid with a new one? What's it do?

7. ### Dave Plowman (News)Guest

Probably to fool the warning system into thinking things are ok?
I'd also be interested to know the purpose of the solenoid.

8. ### AsimovGuest

"James Sweet" bravely wrote to "All" (28 Dec 05 06:59:23)
--- on the heady topic of "Re: Basic question (I think)"

JS> From: James Sweet <>
JS> Xref: core-easynews sci.electronics.repair:352797

JS> Why put a resistor in there though? If the solenoid is bad why not
JS> just leave it disconnected, or replace the solenoid with a new one?
JS> What's it do?

He seems to me intent on disabling the seatbelt beepers. The simpler
thing if he doesn't like beepers is to disconnect the sqwawkbox.

A*s*i*m*o*v

.... I worked hard to attach the electrodes to it.

9. ### T HakemackGuest

OK, here's all the poop.
98-99 Dodge Quadcab trucks have a soleniod that has to be powered to put the
seat belt on. It's powered by a seat belt module under the seat that has a
pendulum(SP) in it that kills power in a wreck to the solenoids thereby
locking the belts. The seat belt module also ties into the Airbag system(I
haven't researched why). Anyway to make a long story short, I put a 2001
seat in it that doesn't use a module(Dodge did away with it after 99).
Basically all I'm doing it faking the module in to thinking the solenoids
are there so the seat belt light on the dash goes out while driving but
still works if you don't have your seat belt on.

10. ### Wes.Guest

I would say the tie in to the air bag system is to adjust air bag timing
and inflation for an unrestrained pax/driver in the event of a crash.

Wes.