HELP!!! Cig. Lighter: 9 ohms between POS and GROUND????

I've been ready to make my changes to my cig. lighter from ignition to
"always on", and I discovered something semi disturbing before I made the
changes.

Between the positive and negative terminals of the cigarette lighter (pos is
center, and ground/neg is shell) I'm expecting 0 resistance. Without that
thing depressed there should be no closed circuit at all, right????

I'm getting ~8 / ~9 Ohms between the two. (power is not supplied by the
battery at this point, so I'm not getting any "stray" readings).

HELP, is this a fire in the making?????

 

Thomas G. Marshall coughed up:

Furthermore, the fuse is pulled when I checked this.

 

Thomas G. Marshall coughed up:

Furthermore, the fuse is pulled when I checked this.

 

Thomas G. Marshall coughed up:

In my haste, I goofed that up of course. I'm expecting infinite resistance,
and instead and receiving 8. (?), which indicates /some/ sort of connection
between the two.

 

Thomas G. Marshall coughed up:

In my haste, I goofed that up of course. I'm expecting infinite resistance,
and instead and receiving 8. (?), which indicates /some/ sort of connection
between the two.

 

What reading do you get with the ignition in the on/run position?

Some circuits rather than going open when off, go to ground when off. Very
important distinction to know to look for when in the business of installing
alarms and such.

 

What reading do you get with the ignition in the on/run position?

Some circuits rather than going open when off, go to ground when off. Very
important distinction to know to look for when in the business of installing
alarms and such.

 

Seth coughed up:

Well, ...... The fuse is /pulled/.

A friend of mine said that cars "in the old days but perhaps still" used to
put capacitors in between the pos and neg of various places in the car to
act as voltage regulators, to smooth out the spikes and valleys.

He's saying that might be supplying the resistance. He also said something
I already knew, that 8 Ohms is suspicious, because it's the resistance of
most speakers.

Any clue here?

 

Seth coughed up:

Well, ...... The fuse is /pulled/.

A friend of mine said that cars "in the old days but perhaps still" used to
put capacitors in between the pos and neg of various places in the car to
act as voltage regulators, to smooth out the spikes and valleys.

He's saying that might be supplying the resistance. He also said something
I already knew, that 8 Ohms is suspicious, because it's the resistance of
most speakers.

Any clue here?

 

Yes, I understand the fuse is pulled, but what I don't know is if the fuse
is before or after the control relay. The fuse could be before the control
relay, and if the control relay goes to ground when off, you would still get
a "shorted" reading with the fuse in or out.

I think that went away a while ago as everything went to more modern
electronics which have that built in per device.

Possibly just an RF reading. What do you get if you do your same test, but
instead of using the casing of the cig lighter as ground, get your ground
elsewhere? Maybe read your pos at the cig lighter, and ground at the fuse
panel or battery (provided your leads are long enough).

Also, maybe be an obvious question, you are "zeroing out" your ohm meter
before taking readings?

Really, all I would do in a case like what you are trying to achieve is take
a 12ga wire, put a 15amp fuse on it (within 6" of source end), a female
spade plug and plug it into one of the BATT connectors at the fuse panel and
run the other end to the pos connector of the cig lighter, capping off the
current pos wire at the cig lighter. Wire tie the new wire out of the way
under the dash and be done with.

When it is time to restore the car to stock, just cut the wire ties, remove
the wire and plug the original plug back into the back of the cig lighter.

 

Yes, I understand the fuse is pulled, but what I don't know is if the fuse
is before or after the control relay. The fuse could be before the control
relay, and if the control relay goes to ground when off, you would still get
a "shorted" reading with the fuse in or out.

I think that went away a while ago as everything went to more modern
electronics which have that built in per device.

Possibly just an RF reading. What do you get if you do your same test, but
instead of using the casing of the cig lighter as ground, get your ground
elsewhere? Maybe read your pos at the cig lighter, and ground at the fuse
panel or battery (provided your leads are long enough).

Also, maybe be an obvious question, you are "zeroing out" your ohm meter
before taking readings?

Really, all I would do in a case like what you are trying to achieve is take
a 12ga wire, put a 15amp fuse on it (within 6" of source end), a female
spade plug and plug it into one of the BATT connectors at the fuse panel and
run the other end to the pos connector of the cig lighter, capping off the
current pos wire at the cig lighter. Wire tie the new wire out of the way
under the dash and be done with.

When it is time to restore the car to stock, just cut the wire ties, remove
the wire and plug the original plug back into the back of the cig lighter.

 

hello, i dont really understand perfectly what you measuring but it sounds
like you are measuring the resistance of two wires that will be 12pos when
the ignition is turned on. my first guess is that they have some kind of
resistor in series with the cigerette lighter to reduce the current, perhaps
the lighter by its self draws too much current. also, maybe some how you are
measuring the internal resistance of the battery. are you measuring this
resistance on a live set of wires?
im guessing they have some kind of resistor in the circuit to reduce current
to the lighter.

 

hello, i dont really understand perfectly what you measuring but it sounds
like you are measuring the resistance of two wires that will be 12pos when
the ignition is turned on. my first guess is that they have some kind of
resistor in series with the cigerette lighter to reduce the current, perhaps
the lighter by its self draws too much current. also, maybe some how you are
measuring the internal resistance of the battery. are you measuring this
resistance on a live set of wires?
im guessing they have some kind of resistor in the circuit to reduce current
to the lighter.

 

Seth coughed up:

Well thanks for your considerate replies. I will try some of your
suggestions, but I proceeded with my installation anyway. Hopefully my car
won't burn to the ground overnight. At least my garage is a detached
one.....

What I've done for my changes are to remove the 10A fuse from the cig. slot,
connect the always on options blade with a wire with an inline fuse (the
same 10A) to a mini-blade (I concocted from a real blade) that I inserted
directly into the cig fuse slot at the side that goes directly to the cig
lighter.

The idea being that I'm reusing the same wiring as before, just powering it
differently at the fuse box.

Interesting, perhaps this sheds some light, and TELL ME IF IT MEANS I SHOULD
UNDO THIS, but a relay clicks on the moment I connected the always on. New
questions:

1. Could the presence of this relay be part of the reason there was a
measurable 8 ohms?
2. Is it ok for a car relay to be "on" all the time?

You have been exceedingly helpful. I'll let you know if this works long
term, or if disaster occurs {shudder}, or if the battery dies.

 

Seth coughed up:

Well thanks for your considerate replies. I will try some of your
suggestions, but I proceeded with my installation anyway. Hopefully my car
won't burn to the ground overnight. At least my garage is a detached
one.....

What I've done for my changes are to remove the 10A fuse from the cig. slot,
connect the always on options blade with a wire with an inline fuse (the
same 10A) to a mini-blade (I concocted from a real blade) that I inserted
directly into the cig fuse slot at the side that goes directly to the cig
lighter.

The idea being that I'm reusing the same wiring as before, just powering it
differently at the fuse box.

Interesting, perhaps this sheds some light, and TELL ME IF IT MEANS I SHOULD
UNDO THIS, but a relay clicks on the moment I connected the always on. New
questions:

1. Could the presence of this relay be part of the reason there was a
measurable 8 ohms?
2. Is it ok for a car relay to be "on" all the time?

You have been exceedingly helpful. I'll let you know if this works long
term, or if disaster occurs {shudder}, or if the battery dies.

 

lamont1 coughed up:

The hot lead to the cig is connected to an empty fuse location (open
circuit).

The ground lead to the cig is connected to the car ground.

I'm not sure what the heck is in-between the two that would somehow connect
them together, even "a little bit", other than something wired in /parallel/
somewhere.

 

lamont1 coughed up:

The hot lead to the cig is connected to an empty fuse location (open
circuit).

The ground lead to the cig is connected to the car ground.

I'm not sure what the heck is in-between the two that would somehow connect
them together, even "a little bit", other than something wired in /parallel/
somewhere.

 

The 8-Ohm sounds like a relay. Your CRV's cigarette lighter is most
likely powering an accessory relay of some sort. To find out, disconnect the
cigarette lighter power at the fuse panel. Then try to operate the suspected
accessory. I've read a few post back regarding an individual who had tried
your method but end up with a drained battery a few weeks later... Locate
the relay and rewire it, or let it defy how you intended to wire it.

 

The 8-Ohm sounds like a relay. Your CRV's cigarette lighter is most
likely powering an accessory relay of some sort. To find out, disconnect the
cigarette lighter power at the fuse panel. Then try to operate the suspected
accessory. I've read a few post back regarding an individual who had tried
your method but end up with a drained battery a few weeks later... Locate
the relay and rewire it, or let it defy how you intended to wire it.

 

If you measure the *resistance* of a capacitor, you will initially get a
low reading that gradually increases to at least hundreds of kiloohms.
How quickly the reading changes depends on your instrument and the
capacitance, but you will not get a steady state reading of 8 ohms.

8 ohms is the *impedance* of most speakers for home use. Most car stereo
speakers have an impedance rating of 4 ohms. Regardless, the DC
resistance (which is what you are measuring with your ohm-meter) is
often less than the rated impedance.

Do you know what else is on the lighter circuit? Lightbulbs give
deceptive resistance measurements. A type 67 bulb is rated 0.69 Amps at
13.5 Volts, which means the resistance is 19.5 Ohms or so *when the bulb
is lit*. If you measure the resistance of a cold, dark 67 bulb you will
read less than 2 ohms. Perhaps there is a light around the lighter
socket that throws off your reading?